What is the likelihood of rain on any given date in Victoria?

The chart below shows the chance of measurable precipitation in Victoria on any given date.  It is based on Environment Canada long term climate data for Victoria Gonzales (1914-2020).  Comparable data for Vancouver, Calgary, and Toronto has also been included for comparison.

The line for Victoria shows a rainy late fall and winter with a distinct summer drought period, characteristic a Mediterranean climate.  The average daily chance of precipitation ranges from a high of more than 60% in November to less than 10% in late July.  The precipitation chance starts at  close to 60% in January, followed by a gradual decrease through the late winter and spring.  By mid-June, the rain chance has dropped to 20%, and it stays in that range until mid-July.  Then there is a very sharp drop, from just over 20% on July 11 to less than 10% from July 20 to August 2nd - that's the time to plan your outdoor activities in Victoria since you are almost guaranteed dry weather!  In early August, the chance of rain once again starts increasing, reaching a peak of 64% by mid-November, when it levels off.  There is a much steeper increase in the likelihood of rain during the late summer and fall compared with the more gradual decrease in the rain chance during the late winter and spring.  

Perhaps not surprisingly, Vancouver follows a similar pattern of dry summers and wet winters, although the chance of rain is consistently higher in Vancouver, ranging from a peak of 70% to a low point of 15%.  This higher chance of rain is to be expected given that Vancouver gets more than twice as much rain overall than Victoria.  Calgary's precipitation pattern is more or less the opposite of Victoria's (or Vancouver's), with the lowest chance of precipitation during the late fall and winter (dropping as low as 15% in early November) and a peak of rainfall during the late spring and summer (topping out at 45% in late June).  Toronto's precipitation pattern shows the least seasonal variation of the four cities, although there still is a dip in the rain chance during the summer, to a low of 28% in mid-August versus a peak of 52% in early January.  

The chance of precipitation is lower in Victoria than it is in Calgary for just under 4.5 months, from May 5 until September 15.  The chance of precipitation in Victoria is lower than it is in Toronto for just over 6 months, from April 1 to October 8.  

How rainy is Victoria compared with other cities in Canada? It depends on where in the region you are.

When talking about Victoria's climate, this blog primarily uses data from the Victoria Gonzales weather station.  This station, located in the southeast part of the City of Victoria near the border with Oak Bay, was Victoria's official weather station for many decades.

Thanks to its southeastern location, precipitation at Victoria Gonzales is strongly impacted by the Olympic Mountain rainshadow.  That influence tends to lessen the further north and west you go in the Greater Victoria region.  Thus, when we've stated on the blog that Victoria gets less rainfall than most cities in Canada, that is based on rainfall in Victoria Gonzales, and is not necessarily true for some of the wetter parts of the region.

Below is a chart that compares average annual precipitation at various locations in Greater Victoria with major cities across Canada.  As you can see, annual precipitation at both Victoria Gonzales (608 mm) and the University of Victoria (643 mm) is relatively low.  Across Canada, only cities in the B.C. Interior and on the Prairies are drier.  In fact, just 18% of Canada's urban population lives in cities with lower annual precipitation than these two locations.   Esquimalt Harbour (861 mm) and the Victoria Airport in North Saanich (883 mm), fall more in the middle of the pack among Canadian cities, with roughly half of Canada's urban population living in cities that are drier than these locations.  Meanwhile, Langford (1133 mm) and Sooke (1236 mm) get more annual precipitation than most cities in Canada: only cities in southwestern B.C., parts of Quebec, and Atlantic Canada get more precipitation.  In fact, 81-86% of Canada's urban population lives in cities that are drier than these locations.

Canadian Climate Comparison: which cities get the most and least rainfall?

In the last post, we compared temperatures in the 41 largest urban areas in Canada (those with 100,000 or more people).  In this post, we'll compare precipitation amounts.

The chart below compares average annual precipitation in the 41 largest cities in Canada, ranked from lowest to highest.  The driest city is Kamloops, in the B.C. Interior, with an average of 287 mm annually.  The remaining top 10 driest urban areas in Canada are mostly in the Prairies, along with two more B.C. cities: Kelowna and Victoria.  People are often surprised that Victoria ranks so high among the driest cities in Canada.  Putting this another way, Victoria gets less annual precipitation than nearly 82% of Canada's urban population.  Victoria's low rainfall is thanks to rainshadowing, from both the mountains on Vancouver Island and from the Olympic Mountains in Washington State.  The wettest of the 41 cities is Chilliwack, followed by Vancouver and Abbotsford.  St. John's and Halifax round out the top 5 wettest cities in Canada.  It's striking that cities in Coastal B.C. occupy the top 3 spots for the wettest urban areas in Canada, while nearby Victoria ranks as the 10th driest out of the 41 cities.

Average Annual Precipitation for Urban Areas in Canada

Seasonal variations in precipitation are also important when comparing Canadian cities.  The chart below ranks summer (June to August) precipitation for Canada's cities.  With just 52 mm of rainfall, Victoria is by far the driest urban area in Canada during the summer.  The next driest city - Kamloops - gets nearly 70% more summer rainfall than Victoria, most cities outside of B.C. - such as Calgary, Toronto, or Montreal - get 4 to 5 times as much summer rainfall as Victoria.  The top 6 driest summer cities are all in B.C. - 4 on the coast and 2 in the Interior.  This really shows the impact of the seasonal variation of precipitation in Coastal B.C.  While we just saw that Vancouver ranks as the second wettest city in terms of total annual precipitation, it is the 5th driest city in Canada in terms of summer precipitation.  The wettest summers tend to be in Atlantic Canada and Quebec.

Average Summer Precipitation for Urban Areas in Canada

Victoria also has relatively dry springs - ranking as the 9th driest among Canadian cities.  Fall precipitation in Victoria is closer to the average, with the city ranking as the 17th driest out of 41 cities.  Winter is a different story.  The chart below ranks winter (December to February) precipitation for Canadian cities.  Saskatoon has the driest winters among Canadian cities, with just 37 mm of precipitation.  The top 10 driest winter cities are all located in the Prairies, the B.C. Interior, or Northwestern Ontario.  Victoria ranks as the 31st driest winter city (or the 11th wettest), with 264 mm of precipitation.  The top 5 wettest winter cities are exactly the same as the top 5 wettest cities overall, with Chilliwack in first place with a whopping 659 mm.

Average Winter Precipitation for Urban Areas in Canada

Victoria's cold winter of 2016-17

We've recently come to the end of meteorological winter (December 1 to February 28), and it was definitely an unusual winter in Victoria.  The biggest stand out was the temperature - this past winter was the coldest in 38 years in Victoria.  The last time we had a winter this cold was back in 1978-79.  Victoria has actually experienced 20 winters in the last 120 years that were at least this cold.  However, all of those winters were prior to 1980, so we're just not used to it  any more!

The mean temperature this past winter was 3.9 degrees, roughly 2 degrees below the 30-year average of 5.8 degrees.  The average daily maximum/minimum this winter was 6.1/1.6, again roughly 2 degrees below the normal winter daily max/min of 7.9/3.6. 

The chart below compares the daily maximum and minimum temperatures this winter with the 30-year average temperatures.  You can see that the temperatures were pretty consistently below average, with just a couple of brief spells of milder weather. 

Daily maximum & minimum temperatures in Victoria, winter 2016-17

Victoria experienced 25 days when the temperature dropped below freezing this winter, compared with the average of 8.8 days.  Again, that’s the most days since the winter of 1978/79.  However, the record was 41 days in 1912/13.  While we had a lot of overnight lows below freezing, it never really got that cold in Victoria this winter.  The coldest temperature was -3.8 degrees on December 17.

Conversely, Victoria experienced daytime temperatures above 10 degrees on just 7 days this winter, compared with the average of 20 days.  Last winter (2015/16) there were 28 days above 10 degrees and the winter before that (2014/15) there were 42 such days - six times as many as this winter.  To put it another way, just 8% of winter days this year were above 10 degrees, compared with 47% of winter days in 2014/15.   

The colder weather was partly the result of a number of arctic outbreaks, bringing cold sunny weather to Victoria.  As a result, total precipitation for the winter was below normal: 222 mm versus the 30-year average of 264 mm.  The chart below compares the daily and cumulative precipitation at Victoria Gonzales this past winter with the 30-year normal precipitation.  While December was a bit wetter than normal, January was very dry and February was about average.  The highest daily rainfall was 26 mm on February 9.  Overall, there were 46 days with measurable precipitation this winter, which was right on the average.

Daily & cumulative precipitation in Victoria, winter 2016-17

As usual, Victoria was much drier than surrounding areas, as shown in the chart below.  Compared with Victoria Gonzales (222 mm), the Victoria Airport (315 mm) had 50% more precipitation, while Seattle (430 mm) and Vancouver (469 mm) both had about twice as much. 

Winter 2016/17 brought the first significant snowfall in 5 years to Victoria.  Not surprisingly, snowfall was above normal.  Total snowfall for the winter was 29 cm, almost double the 30-year average of 16 cm for December to February (total annual snowfall averages 20 cm in Victoria).  There was 8 cm of snow in December, just 1 cm of snow in January, and a whopping 20 cm in February (versus normal of 9 cm for December, 3.4 cm for January, and 3.6 cm for February). In terms of days with snow on the ground, Victoria got off not too badly (especially compared with Vancouver and up-Island): there were 5 days with at least 1 cm of snow on the ground this winter compared with the normal of 4.5 days during December to February.

BC Day - the most reliable weather of the year in Victoria

I'm continuing my look at average weather on major holidays in Victoria.  We last looked at Canada Day - next up is BC Day.

BC Day doesn't fall on a specific day - it is the first Monday in August.  That means, it can fall anywhere from August 1 to 7.  For the purposes of this discussion, I will use the weather averages for August 1-7.  This period is right in the middle of the driest, sunniest, and warmest time of year in Victoria (which generally extends from mid-July to mid-August).  

Looking at the 1981-2010 period, there is just a 9.1% chance of measurable rain on BC Day.  By comparison, the chance of rain is 14.4% on Canada and 20.0% on Labor Day, so the BC Day long weekend is definitely the most reliable for camping or other outdoor activities.  In fact, Victoria's weather on BC Day is more reliably dry than any other city in Canada.  The chance of measurable rain on BC Day is nearly twice as high in Vancouver (16.7%), and nearly four times as high in Calgary (33.2%) and Toronto (33.3%).

BC Day is also generally the sunniest holiday in Victoria.  There is a 97.3% chance of getting measurable sunshine on BC Day in Victoria.  On average Victoria gets 10.5 hours of sunshine on BC Day, meaning that it is sunny about 72% of daylight hours.  That compares with 9.3 hours (60% of possible) on Canada Day.  While that's impressive, BC Day actually just misses the sunniest time of year in Victoria: during the last 10 days of July there is an average of 12.1 daily hours of sun, meaning it is sunny 81% of daylight hours during this period.  Again, Victoria is more reliably sunny on BC Day than other major cities across Canada.  While Victoria gets 72% of possible sunshine on BC Day, Vancouver and Calgary both average 63% and Toronto averages 58%.  Even Penticton in the "sunny Okanagan" averages just 62% of possible sunshine on BC Day.

The average high and low temperature for BC Day at Victoria Gonzales is 20.6/11.9 degrees, making it the warmest holiday of the year.  The warmest it's been during the first week of August is 32.8 degrees on August 6, 1942 (which was also the year Victoria had its hottest Canada Day on record).  The temperature gets above 20 degrees about half the time during the first week in August at Victoria Gonzales.  It's a different story if you  move inland in the Victoria region: at the University of Victoria, the average temperature during the first week in August is 24.0 degrees, and it gets above 20 degrees nearly 90% of the time during the first week in August, and above 25 degrees nearly 40% of the time.

Holiday weather - Canada Day

I thought I would start a series looking at the typical weather in Victoria for various holidays.  First up is Canada - July 1.

While Canada Day doesn't quite fall in the very driest time of year in Victoria (which begins about a week or so later), it is still quite dry.  We actually had a few light sprinkles on Canada Day this year (2016), but there was no measurable rainfall at Victoria Gonzales.  If you look at the full period of record at Gonzales, going back to 1898, there has been measurable precipitation on 14.4% of those years.  More recently, it's been even drier on Canada Day: in the last 22 Canada Days going back to 1995, there has only been measurable rainfall once, when 0.8 mm fell on Canada Day 2010.  That works out to a 4.5% chance.  When it has rained on Canada Day, amounts have generally been light, and the average precipitation for the day (including all those years with no rain) is just 0.3 mm.  The most rain ever recorded on July 1 in Victoria was 8.6 mm in 1933.

Our neighbors to the north in Vancouver don't fare nearly so well when it comes to having a dry Canada Day.  The chance of having measurable rainfall on July 1 in Vancouver is 32% and the average amount of rainfall 3.1 mm - ten times as much as Victoria.  Even if you just look at the 1995-2016 period, which has been so dry on Canada Day in Victoria, it has been much wetter in Vancouver, with measurable rainfall on 8 of those 22 years.

There's a much better chance of having measurable sunshine in Victoria on Canada Day than having measurable rain.  During the period from 1951-1988, there was measurable sunshine on Canada Day 89% of the time.  That's actually quite low compared with other days nearby in the calendar: during that same period, every June 30 had measurable sunshine (100%) while on July 2 there was measurable sunshine 97% of the time.  The average amount of sunshine on Canada Day is 9.3 hours, or about 60% of the 15.6 hours that's possible for that date.

The average high and low temperature for Canada Day at Victoria Gonzales is 19.4/10.8 degrees.  The warmest July 1 was 1942 when the temperature hit a sweltering 33.9 degrees.  The coolest was 1979 when the temperature topped out at a very chilly 13.0 degrees.  The temperature gets above 20 degrees at Victoria Gonzales on only about one third of Canada Days.  It's a different story if you  move inland in the Victoria region: at the University of Victoria, the average temperature on July 1 is 22.9 degrees, and it gets above 20 degrees nearly 80% of the time on Canada Day.

The Mild Streak Continues in March

I'm a little late, but I'm finally getting around to looking back at last month's weather!

The mild streak continued in March, with a mean temperature of 9.1 degrees, compared with a 30-year March average of 7.8.  That's warm enough to make it into the top 10 warmest Marches in the past 118 years at Victoria Gonzales.  The average daily maximum and minimum this March were 11.9 and 6.2, compared with the  normal 11.0 and 4.8.  The warmest temperature was 18.0 on the 30th and the coolest was 3.2 on the 16th.

The chart below compares the daily maximum and minimum temperatures this month with the 30-year averages.  You can see that temperatures were generally above average, particularly at the end of the month.  The daily minimum temperature was above average for 23 of 31 days in March.

March 2016 Temperatures in Victoria

March 2016 was quite close to average in terms of precipitation, with 56 mm compared with the average of 50 mm.  The chart below compares the daily and cumulative precipitation for the month with the average cumulative precipitation.  You can see that the month started out quite wet, and by mid-month we were were at almost double our normal precipitation.  However, the second half of the month was dry so were were only slightly above normal by the end of the month.  There was measurable precipitation on 16 days, slightly more than the normal of 15 days.  The wettest day was the 9th, with 15 mm of rain.

March 2016 Daily Precipitation

The chart below compares Victoria's total precipitation in March 2016 with some nearby locations.  As is typical, Victoria was a lot drier.  Compared with Victoria (as measured at the Gonzales weather site),  the Victoria Airport had just over double the rainfall - 119 mm vs 56 mm.  Nanaimo was particularly wet this March, with 247 mm - more than four times as much rain as Victoria. Vancouver, with 198 mm had almost four times as much rain while Seattle, with 140 mm, had about 2.5 times as much rain as Victoria.

March was also another month with no snow in Victoria, which also means another winter with no snow.  We have now had four winters in a row with no snow.  The last time Victoria saw snow accumulate on the ground (more than 1 cm) was January 2012.

Which has a better climate - Vancouver or Victoria?

I thought I'd start a series of posts that compare Victoria's climate with the climate in other cities - call it a climate smackdown.

First up, is Vancouver.  I think most people in Victoria are aware that our climate is a lot drier and sunnier than Vancouver's thanks to the rain shadow, but I want to take a look in a bit more detail.

Let's start with precipitation.  As the chart below shows, Vancouver does get a lot  more precipitation than Victoria - an average of 1,560 mm annually vs 641 mm for Victoria.  That's almost two and a half times as much rain!  Vancouver gets more precipitation than Victoria throughout the year, but there are important variations.  During the late fall and winter rainy season from October to February, Victoria gets a little under half as much precipitation.  However, during the drier months, the difference is even greater, with Victoria getting less than one third as much rain as Vancouver between March and September.

The difference between Victoria and Vancouver is very distinct.  In both cities, precipitation has been recorded for almost 120 years.  During that time, the wettest year in Victoria was 1933, when 945 mm of precipitation was recorded.  Not only is Victoria's wettest year on record still drier than an average year in Vancouver (1,560 mm), but it is drier even than the driest year every recorded in Vancouver (962 mm in 1929).

We can also compare the frequency of precipitation.  For example, Victoria averages 133 days per year with measurable precipitation versus 166 days in Vancouver - so Vancouver averages about an extra month's worth of rainy days each year.  We can go even further and look at the number of hours with precipitation: Victoria averages 1141 hours while Vancouver averages 1658 hours - about 45% more.  Based on these numbers, most of the difference in total annual precipitation is not primarily because it rains more frequently in Vancouver, but because, when it does rain in Vancouver, the rain is on average nearly twice as heavy as when it rains in Victoria.

It's interesting to note that despite Vancouver having a reputation that it "rains all the time", the average 1658 annual hours with precipitation amounts to only about 19% of the time, while it's dry 81% of the time.   In Victoria, there is precipitation just 13% of the time while it's dry 87% of the time.  Even in the wettest winter month (December), it's dry 69% of the time in Vancouver and 78% of the time in Victoria.  During the driest month (July), it's dry 92% of the time in Vancouver and more than 95% of the time in Victoria.  The chart below shows the frequency of precipitation in Victoria and Vancouver throughout the year.

Vancouver gets nearly twice as much snow as Victoria, with an average 37 cm annually in Vancouver versus 20 cm in Victoria.  Victoria is more than twice as likely than Vancouver to experience a winter with little or no snow.  Over the past 30 years, Victoria has experienced 14 winters with less than 5 cm of snow for  the entire winter, compared with just 6 such winters for Vancouver.  Snow is also more likely to stay on the ground longer in Vancouver, with an average of 8 days each winter with at least 1 cm of snow on the ground compared with 5 days for Victoria.

Victoria is also sunnier than Vancouver, with an average 2,203 hours of sunshine annually versus 1,825 hours for Vancouver.  Victoria averages 315 days per year with at least some measurable sunshine, leaving an average 50 days per year with no sun.  Vancouver averages 76 days annually with no measurable sunshine - about 50% more than Victoria.  As with precipitation, the difference in annual sunshine between Victoria and Vancouver is quite distinct.  The cloudiest year on record in Victoria - with just 1,948 hours of sunshine recorded way back in 1914 - was still much sunnier than the average for Vancouver.  Conversely, the sunniest year on record in Vancouver - 2,109 hours recorded in 1987 - was still much cloudier than the average for Victoria.

Up to now, I think you can safely say that Victoria is clearly winning this climate smackdown.  But now we take a look temperature, and things become more complicated.  The chart below shows the average daily maximum temperature in Victoria versus Vancouver.  The average high temperature in Victoria is almost a degree warmer than Vancouver during the winter months, and it's about the same during the fall and early spring, but it is significantly cooler during the late spring and summer.  It's about 2 degrees cooler in July and August - averaging 20.5 degrees in Victoria versus 22.4 degrees in Vancouver.  The numbers in the chart are based on Victoria Gonzales, located right on the Strait of Juan de Fuca.  Away from the Strait, at the University of Victoria, the average high temperature in July and August is 23.7 degrees - more than 3 degrees warmer than Gonzales.  Nonetheless, Victoria is known for its relatively cool summers - particularly in the southern part of the region near the Strait of Juan de Fuca.  The Vancouver numbers are for Vancouver Harbour.  While this is also near the water, the Strait of Georgia is not nearly as cool as the Strait of Juan de Fuca during summer, so the cooling effect is less.  However, inland locations in the Vancouver region do have summer daytime highs that are 1-2 degrees warmer than the Vancouver Harbour numbers shown.

The next chart shows the average daily overnight lows in Victoria versus Vancouver.  Again, Victoria is nearly a degree warmer than Vancouver during the winter months.  Another way to look at this is to compare the average numbers of days each winter when the overnight low drops below freezing.  Vancouver averages almost twice as many "frost" days: 18.0 versus 9.5 for Victoria.  Victoria has experienced 7 winters in the past 118 years when the temperature did not drop below freezing for the entire winter.  Vancouver has never recorded a frost-free winter.  But while Victoria has warmer overnight lows in the winter, Vancouver has much warmer overnight lows during the summer.  During July and August, Victoria has an average overnight low of 11.8 degrees versus 14.4 degrees in Vancouver.  Victoria is definitely not known for its sultry summer nights!  Of course that could be a good thing if you don't have air conditioning!

What makes a good climate is quite subjective, but I think that overall Victoria beats Vancouver.  The drier, sunnier weather, with less snow and frost more than offsets the sometimes cool summer days and chilly summer nights.

A Look at Winter 2015/16

The end of February is also the end of meteorological winter (December to February).  So what was winter like in Victoria?

First, it was mild.  The mean temperature over the three month period was 6.8 degrees - a full degree above the 30-year average of 5.8 degrees.  Winter 2015/16 tied for the 7th warmest winter on record in Victoria (with 118 years of record-keeping), although it was still well below the all time record of 7.6 degrees which we hit last winter.  The average daily max/min temperature this past winter was 8.9/4.8.  The warmest temperature was 14.0 on February 9th and the coldest was -0.9 on December 31st.  There were 5 days when the temperature dropped below 0, which all occurred between December 30th and January 2nd.  The 30-year average for Victoria Gonzales is 7.6 days with overnight temperatures dropping below freezing during the winter.

The chart below shows the daily maximum and minimum temperatures this winter, compared with the 30-year averages.  You can see that, except for the last 10 days of December and the first 10 days of January, temperatures were pretty consistently above average.  This is an El Nino year, so the mild temperatures are to be expected.  In fact, the mean temperature this winter of 6.8 degrees was the same as the average for the past 6 moderate or strong El Nino winters, as discussed here.

Daily max & min temperatures, winter 2015/16

This winter was also a little wetter than normal, but not by much.  Total precipitation from December to February was 280 mm, compared with the 30-year average of 259 mm.  The chart below shows the daily and cumulative precipitation this winter compared with the average.  You can see that precipitation ran a little ahead of normal in December.  This was followed by a dry January, with just 47 mm of rain.  Most of February was quite dry as well, but the heavy one day rainfall we received on the 15th pushed us above normal for the season.

Victoria's 280 mm of precipitation this winter compared with 681 mm in Vancouver and 626 mm in Seattle (where it has been the wettest winter rainy season on record).

There was no snow this winter, and it continues a snow drought for Victoria.  We had a couple of light dustings of snow during the winter of 2013/14, but you have to go back to the winter of 2011/12 for the last time we had significant snowfall (more than 3 cm).  That's four winters in a row now with little or no snow.

February blahs? Not in Victoria!

You often hear the term February blahs, especially from people in other parts of Canada who are tired of the cold, snow and slush, and they know that they probably have a couple more months of winter to endure.  I think this is the time of year when I am most appreciative of living in Victoria.  This may not be the nicest time of year in Victoria, but compared with most of the rest of Canada, it is heaven.  (It was -26 degrees in Toronto this morning, although granted that is very cold even for them!)

versus

As I mentioned in this post, while February is still the depth of winter in many parts of Canada, the coldest and dreariest point of the winter in Victoria tends to happen quite early, around the end of December.  By February, the weather is noticeably warmer, drier, and sunnier.  The average high temperature in February in Victoria is 9 degrees, a degree warmer than January and nearly two degrees warmer than December.

February is also noticeably drier, with an average of just 61 mm of precipitation compared with more than 100 mm each month in November, December, and January - the end of the rainy season is definitely in sight!  On average, there is a 43% chance of measurable precipitation on any given day in February (compared with than 50% in November, December, and January).  As I've said before, I think looking at the % chance of rain on any given day somewhat overstates how rainy it is, since a day with measurable precipitation doesn't necessarily mean rain all day - it could be a brief shower.  Another way to look at at this is the % of hours with measurable precipitation, and for Victoria in February there is precipitation just 19% of the time.

The sun is also making more of an appearance, with 98 hours of sunshine in a typical February in Victoria.  That works out to an average of 3.5 hours per day, compared with only 2.3 hours per day in January and 2.0 hours per day in December.  On average, February gets 22 days with at least some measurable sunshine, and overall, it is sunny about 35% of the time (at least during daylight hours!).  In other words, during daylight hours it's actually more likely for the sun to be shining February (35% of the time) than it is to be raining (19% of the time).

Snow is also pretty rare in February in Victoria.  Over the past 30 years, only 11 Februarys have seen any snow at all and just 5 of the past 30 Februarys saw significant snowfall (more than 10 cm).  When it does snow, it melts quickly; Victoria averages just 0.7 days with snow on the ground during February.

The other nice thing about February is that it's springtime!  Crocuses, daffodils, and rhodos are blooming, and the cherry blossoms are out.  Sometimes when we have mild weather in February, they will also get warm weather in Southern Alberta, with temperatures in the teens.  While that must be a nice break from the cold and the snow, it's so much nicer to enjoy the mild weather here when there is greenery and flowers everywhere!  Here's a few photos I took last week (February 8) around Victoria:

Rhododendrons at Beacon Hill Park

Camelias

Irises

Even the bees are out

Finally, here is a link to a great video that really sums up how nice February can be in Victoria.

Another Rain Shadow

Continuing our pattern from January, we had another good rain shadow today.  Here's the radar from about 4:30 this afternoon:

The rain shadow seems quite strong.  Sometimes only the very southeastern part of Victoria is in the rain shadow, but this one is extending out west towards Sooke and north towards Sidney.

A look at the daily rainfall totals as of 6 pm:

0 mm at most sites in Victoria, Esquimalt, Oak Bay and Saanich
0.5 mm in Sidney
6 mm in Sooke
8 mm in Duncan
16 mm in  Ladysmith
18-20 mm at most sites in Nanaimo

But as a write this, I can hear a few drops of rain starting to fall.  Here's the latest radar, from just before 6 pm:

It looks like the rain may starting to move in.  It was nice while it lasted!

A dry and mild January in Victoria

It’s February 1, and time for a look back at the weather for January 2016. 

The most notable feature about the weather this past January was the low total rainfall – just 47 mm compared with the 1981-2010 average of 104 mm of precipitation at Victoria Gonzales, making it the tenth driest January in 118 years of record keeping.  It may surprise you that January was so dry.  That may be because the number of days with measurable precipitation was actually slightly above average - 20 days this January versus 19 on average - but the rainfall amounts on those rainy days was significantly lower than normal.  

I’ve talked previously about the effect of the Olympic Mountain rain shadow in reducing the amount of precipitation over Victoria, and January was a prime example of that.  There were numerous days in January when there was heavy rain to the north and west, but Victoria received just a few sprinkles.  For example, the Victoria Airport – 25 km north of Victoria and outside the Olympic rain shadow – received 138 mm of precipitation in January, quite close to its normal of 143 mm.  Total precipitation amounts at the other Environment Canada weather sites in the Victoria region include 54 mm at the University of Victoria  and 75 mm at Esquimalt Harbour (which is further west and gets less rain shadowing).  

I thought it would be interesting to look in a bit more detail at the variation in rainfall around the region in January.  Victoria's School Based Weather Station Network has dozens of weather sites in the Victoria region, so I have used statistics from those sites in the chart below, which compares the January 2016 precipitation total at various sites around Greater Victoria.  You can see the impact of the rain shadow, especially in the southern and eastern sections of the region.  Some of the wetter locations in the region received nearly four times the precipitation in January than Victoria Gonzales.  

Perhaps I will try to create a map to show this at some point!

It’s also interesting to compare Victoria's January 2016 precipitation with other locations outside Greater Victoria.  As the chart shows, Pender Island (one of the drier locations on the Gulf Islands) got about 2.5 times as much rain as Victoria.  Nanaimo and Seattle both got about 4 times as much rain, while Vancouver and Courtenay received nearly 4.5 times as much rain.  Out on the exposed west coast of Vancouver Island, Ucluelet received a whopping 429 mm of rain - nearly ten times Victoria's total.  Thank you rain shadow!

There was no snowfall in Victoria during January, although some outlying areas did receive a dusting of snow.  For example, there was 3 cm of snow recorded at the Victoria Airport.  The last time Victoria received significant snowfall was January 2012.

Temperatures in January were a little above the average.  At Victoria Gonzales, the average daily high for the month was 8.1 degrees and the average daily low was 4.4, resulting in a mean monthly temperature of 6.2 degrees. That compares with the 1981-2010 average of 5.9 degrees.  The chart below compares the actual temperature trend (in green) with the average daily highs and lows for January.   The month started well below average, then gradually increased, reaching above average temperatures for most of the second half of the month.  The milder temperatures are consistent with an El Nino year, although it wasn’t as warm as during past El Nino years when the January temperature has averaged 6.8 degrees, as I discussed here.  The warmest recorded temperature during the month was 12.8 on January 22  and the coldest recorded temperature was -0.5 on January 2.  There were 3 days (the first three days of the month) with temperatures below freezing, which was close to the average of 3.4 days. 

One note on the Victoria Gonzales precipitation total.  The Environment Canada weather site at Gonzales was missing precipitation data for some days in January 2016.  Luckily, there are two Victoria School Based Weather Stations  within 500-600 m of Gonzales: Margaret Jenkins Elementary and SMU.  I used an average of these two sites to fill in the missing data for Victoria Gonzales.  

What's the chance of rain and the likelihood of sunshine throughout the year in Victoria?

The chart below shows the % chance of precipitation and the % of possible sunshine on any given day during the year in Victoria.  It's really striking how the likelihood of precipitation and sunshine form a mirror image of each other.

Let's start by looking at the blue line - the chance of precipitation on any given day.  This starts in the 50-60% range during January and February, drops below 50% in March, and gradually declines until it reaches about 20% in June and early July.  Then we see something that is very distinctive of the climate in our area - a sharp drop down to about a 10% chance of rain on any given day from roughly the second week of July until mid-August.  That's definitely the time to plan your camping trip or outdoor event if you want to almost guarantee dry weather!  Beginning in mid-August, the chance of rain begins to increase, back to about 20% by the end of August, then gradually increases to about 25% by the end of September.  Unlike the spring, when there is a very gradual decrease in the likelihood of rain, the increase in the fall is much more abrupt, doubling from roughly 25% at the end of September to more than 50% by the end of October.  November and December put the chance of precipitation back in the 50-60% range where they started the year.

This pattern is quite different from other locations in Canada.  In Toronto, for example, the chance of precipitation on any given day varies much less throughout the year, from a high of about 50% during the winter months dropping to 30-35% during the summer.  The pattern is even more different in the Prairies.  In Calgary, there is only a 20-25% of precipitation on any given day during the winter months, but that increases to a 40-50% chance during June and July.

As I mentioned earlier, the % of possible sunshine in Victoria - the red line on the chart - follows almost the exact opposite pattern that chance of precipitation does throughout the year.  Victoria gets less than 30% of possible sunshine in December and January.  This gradually increases to about 60% by the beginning of May and stays at that level until the very beginning of July.  Then just as the chance of precipitation plummets from 20% down to 10% in the second week of July, the % of possible sunshine shoots up from about 60% to over 80%.  Again, this is the time to plan those outdoor activities!  The % of possible sunshine begins to drop off in the second week of August, and by the end of the month it is back down around 60%.  Possible sunshine declines very gradually at around 55% through September and the first half of October, then there is a sudden drop down to 30% by the beginning of November.  I've always noticed that the first half of October tends to have much nicer weather in Victoria than the second half -there's often a very abrupt change midway through the month - so it was nice to see this validated by the statistics!

In some ways, the seasonal pattern of sunshine in Victoria is quite similar to that in Toronto, where % of possible sunshine varies from about 30% during November, December, and January then gradually increases to around 60% in July before gradually declining once again.  The big difference is that Toronto doesn't experience Victoria's very high midsummer sunshine levels (80%).  So why is that?  As I explained in this post, the main reason is the North Pacific High, which tends to park itself over the northeastern Pacific in the summer months, deflecting weather systems to the north and providing Victoria with sunny, dry weather.  This is enhanced by the Olympic Mountain rain shadow and by Victoria's location surrounded by the cool water of the Strait of Juan de Fuca, which inhibits the formation of convective clouds and thunderstorms, resulting in exceptionally clear skies in the summer.  That's also why Victoria holds the record for the sunniest month ever recorded in Canada, outside the far north (in fact it holds the top three spots).

I should just mention one more thing.  While I have talked about the chance of precipitation and the % of possible sunshine as forming mirror images of each other, you should note that the way we're measuring chance of rain versus chance of sun is quite different.  For precipitation, we're looking at the % chance of any measurable precipitation on a given day.  That means a day where it there is a light shower for 10 minutes resulting in 0.2 mm of rain would be classed as a day with precipitation.  On the other hand, for sunshine we are not looking at the % chance of measurable sunshine, we are looking at % of possible sunshine.  The % chance of measurable sunshine would be much higher: throughout the year, Victoria averages about 51% of possible sunshine, but on average there is measurable sunshine (at least 0.1 hours) on 317.7 days, or 87% of days during the year.    So just keep in mind that while the chart above might make it seen like the likelihood of rain and sunshine is about the same in Victoria - just a mirror image - in fact we get a lot more hours of sunshine annually than we get daylight hours with rainfall.

A nice rain shadow yesterday

I've mentioned how the Olympic Mountain rain shadow has such a profound impact on Victoria's climate.  Thanks to this effect, the Victoria Gonzales weather station averages only 641 mm of precipitation annually, compared  more than 1000 mm in Metchosin (20 km west) and more than 3500 mm at Port Renfrew (80 km west on the exposed southwest coast of Vancouver Island).

Yesterday, we had a good example of a rain shadow.  Here's what the radar looked like around midday yesterday:

You can see there is a pretty clear hole in the rain over Victoria, as well as the northeast Olympic Peninsula.  That "hole" persisted for most of the day and there were only a couple of light sprinkles.  Meanwhile, there was steady rain all day up at the Victoria Airport, with rain recorded every hour from 4 am until midnight yesterday.

The precipitation totals from yesterday also tell the story.  There was just 1.4 mm of rain at Victoria Gonzales and 1.5 mm of rain at the University of Victoria weather station.  At the Esquimalt weather station, about 8 km west of Gonzales, there was 5 mm of rain.  At the Victoria Airport, 25 km north of Victoria, there was more than 14 mm of rain - ten times the amount that fell at Gonzales.  Rainfall totals at up-Island locations were even higher: 26 mm in Duncan, 24 mm in Nanaimo and 28 mm in Campbell River.

The rain shadow tends to be centered over the eastern part of the Strait of Juan de Fuca, as shown in the map below from the informative website OlympicRainShadow.com.

Sequim and Port Townsend, Washington, which are located closest to the center, feel the greatest impact from the rain shadow.  Port Townsend averages only 484 mm of annual precipitation, while Sequim receives a mere 407 mm.  A little further west, Port Angeles averages 642 mm - roughly the same as Victoria Gonzales.  The rain shadow area is not static; it tends to wobble around, so sometimes Victoria is in the rain shadow while other times it is just off to our southeast.  Because Victoria is on the northwestern edge of the rain shadow, areas immediately to our west and north see little or no impact from it (although areas to the north, including the Victoria Airport and the Gulf Islands, do benefit from the less potent rain shadow produced by the lower Vancouver Island mountains).

The Victoria Gonzales weather station is located in that part of the Victoria region that is most impacted by the rain shadow.  Interestingly, the Victoria School-Based Weather Station Network opened a weather station on Trial Island in 2013.  Trial Island is located off the south coast of Oak Bay, about 2 km southeast of Victoria Gonzales, so it is the piece of land in the Victoria Region that is closest to the rain shadow.  Annual data for 2014 and 2015 show that the Trial Island station received only about 400 mm of rain in each of these years, substantially lower than Gonzales.  I'm not sure how accurate these measurements are, and I suspect they may underestimate the rainfall at Trial Island somewhat, but it is likely that the Trial Island weather station occupies the driest site measured on the British Columbia coast, a title long held by Victoria Gonzales.

Does Victoria have a Mediterranean Climate?

You may have seen Victoria described as having a Mediterranean or perhaps a sub-Mediterranean climate.  Is this just local boosterism?  People are sometimes skeptical about these claims of a Mediterranean climate.  After all, while we have great weather in Victoria, it’s not exactly southern California or the Greek Islands.  Despite the skepticism, there is in fact truth to these claims. 

The Koppen classification system, developed by Russian German climatologist Wladimir Koppen in the late 19^th century,  is one of the most widely used climate classification systems in the world.  Under the Koppen system, the world’s climates are classified into five main groups: A – Tropical, B – Dry, C – Temperate, D – Continental, and E – Polar.  Victoria falls in the the Temperate group, which is further classified based on the annual precipitation pattern, indicated by the second letter in the classification: s for dry summer, w for dry winter, and f for precipitation throughout the year.   So Cf would include Oceanic climates, like London, England, while Cs climates are termed Mediterranean.  To meet the criteria for a Cs climate, summer months must have less than one third the precipitation as the wettest winter month, and summer months must have less than 30 mm of precipitation.  Victoria easily meets these criteria, with July rainfall of just 13 mm – less than one tenth of our wettest month in December.  Mediterranean climates are further classified as Csa or Csb, depending on whether summers are hot (mean monthly temperature above 22 C) or warm (mean monthly temperature below 22 C).  Based on all these criteria, Victoria’s climate is classed as Csb, or warm summer Mediterranean.  Other locations with a Csb climate include San Francisco, Cape Town, and Porto, Portugal. 

The charts below show the monthly precipitation in Victoria, San Francisco, and London, England.  All three cities have roughly similar total annual precipitation - about 600 mm.  However, while precipitation in London is evenly distributed throughout the year, Victoria and San Francisco have the distinctive Mediterranean pattern of winter rainy season and summer drought   While Victoria's summer drought period is not quite so intense as San Francisco's, the overall pattern is still the same.

Further evidence of our Mediterranean climate can be seen in Victoria’s native vegetation, which tends to be a strong expression of the local climate.   While the vegetation of northern and western Vancouver Island can be classified as temperate rainforest, the southern and eastern coasts of the Island have a drier Coastal Douglas Fir Ecosystem.  In the driest parts of this ecosystem, particularly around Victoria, a sub-class – Garry Oak Meadow – can be found.  This is essentially a temperate savannah, with clumps of oak forest interspersed with meadows and more open prairies.  The Garry Oak is the only native oak tree in Western Canada.  Garry Oak Meadow is now an extremely rare and threatened ecosystem in Canada since most of it has been covered by development in the Victoria area.  The picture below shows a Garry Oak meadow in Uplands Park near Victoria, taken in April when the wildflowers are blooming and before the meadow dries out during the summer drought.    

This type of ecosystem can be found in Oregon’s Willamette Valley, and also stretches down into parts of central California.   Sometimes when I have been driving down in California I will pass through an area of low hills covered with golden grass and clumps of oak trees, and it is striking how much it looks like the undeveloped parts of Victoria in the summer.

The following quote is an indication of how different the natural vegetation in Victoria is from surrounding regions along the B.C. coast.  It comes from Sir James Douglas, the first Governor of Vancouver Island, when he was surveying the region for a potential location for Fort Victoria in February 1843:

“The place itself appears a perfect ‘Eden’ in the midst of the dreary wilderness of the North west coast, and so different is its general aspect from the wooded, rugged regions around that one might be pardoned for supposing it had dropped from the clouds into its present position.”

Douglas chose the site because it was surrounded by so much open meadow and prairie land.  Douglas was visiting Victoria in the spring, and seeing the luxuriant growth of the meadowland, he assumed that the area would be perfect for growing crops through the summer months, writing that  “the climate being also mild and pleasant, we ought to be able to grow every kind of grain raised in England”.   After his first summer in the region, Douglas had learned that Victoria’s dry summers would make agriculture more challenging than he’d originally thought, writing in a letter dated November 1843 that  “no rain fell between the 10th of June and 8th September at Fort Victoria” and that the residents of Victoria were “at times badly off for water”. 

So Where is El Nino?

El Nino has really started to make its presence felt in California over the past few days, with a series of storms bringing lots of rain to coastal areas - just what you would expect during an El Nino winter.  For Victoria, the conventional wisdom is that we tend to experience winters that are warmer and a bit drier than normal during El Nino years.  This year's El Nino has been touted as the largest one ever recorded, so has our winter weather lived up to the expectation so far?  Not really.

First, let's look in a little more detail at how El Nino usually impacts our winters in Victoria.  Over the past 30 winters, there have been 6 moderate or strong El Ninos: 1982-83, 1986-87, 1991-92, 1997-98, 2002-03, and 2009-10.

The table below looks at the monthly mean temperature in Victoria for December through March, comparing El Nino winters with the 30-year average.  Each month between December and March has been, on average, warmer during El Nino winters.  The difference is smaller in December and March (+0.8 degrees) but increases in January and especially February, when it peaks at a difference of +1.1 degrees.

           Mean Monthly Temperature

	Dec	Jan	Feb	Mar
1981-2010 ave.	5.3	5.9	6.5	7.9
El Nino winters	6.1	6.8	7.6	8.7
Difference	0.8	0.9	1.1	0.8

The next table compares average precipitation in Victoria during the same months.  The results are much less conclusive, with December and especially February being somewhat drier during El Nino winters, but January and March being slightly wetter.

    Average Monthly Precipitation (mm)

	Dec	Jan	Feb	Mar
81-10 ave.	95	104	61	51
El Nino	89	111	49	55
Difference	-6%	7%	-20%	8%

One aspect of our winters that has been significantly impacted by El Nino seems to be snowfall.  The 30-year average snowfall for Victoria is 20.1 cm.  However, for the 6 El Nino winters in the past 30 years, snowfall has averaged just 1.4 cm, or 7% of normal.  Now that's a significant difference!

So how has this winter stacked up?  December was 0.9 degrees above the 30-year average, or about what you'd expect for an El Nino winter.  However, that warmth all seemed to come in the first half of the month.  Late December, and so far in early January, temperatures have been below normal.  Precipitation in December was about 25% above normal, while so far in January it has been relatively dry.   So precipitation has been a mixed bag, but that seems to be the trend for El Nino winters in Victoria.  There has been no snow so far this winter in Victoria, so that certainly seems to follow the pattern we've seen in previous El Nino winters.  

For an El Nino that's been hyped as the biggest ever recorded, so far it seems a bit of a let down in Victoria.  The weather has been pretty chilly for about three weeks now.  One thing to keep in mind though, is that El Nino tends to have its greatest impacts in Victoria later in the winter, peaking in February.  Let's hope this monster El Nino brings us a really mild and dry February!

Monthly Review: December 2015

While, statistically, Victoria didn't experience a lot of extreme weather in December 2015, it was an interesting month.

The mean temperature for the month at Victoria Gonzales was 6.2 degrees, almost a degree warmer than the 30-year average of 5.3.  December saw an average daily high of 8.1 and an average low of 4.3, again warmer than the average high/low of 7.2 / 3.3.  However, these monthly averages mask what was almost two different months when it came to temperature.  The first half of the month was very mild - in fact the second mildest Dec 1-15 on record - with a mean temperature of 8.2 degrees and an average high/low of 10.0 / 6.3.  The second half of the month got much chillier - nearly 2 degrees below average - with a mean temperature of 4.4 and an average high/low of 6.3 / 2.5.

The warmest day of the month was 12.8 on December 8.  There were 7 days when the temperature topped 10 degrees, all between Dec. 3 and 11th.  The coldest overnight low of the month was -0.9 on December 31.  There were 2 nights when the overnight temperature dropped below freezing - December 30 and 31.  In an average December, Victoria Gonzales gets 3 nights below 0.

December was a rather wet month, with rainfall measured on 21 days, compared with the average 17.5 days for December.  Total precipitation for the  month - all rain - was 120.2 mm, 27% more than the December average of 94.8 mm.  Precipitation was also above normal at the Victoria Airport: 163.9 mm compared with the average of 142.5.  To our south, it was even wetter: Seattle had its second wettest December on record, with 285 mm and Portland had its wettest December on record with 387 mm!  The record for Victoria Gonzales is 331 mm back in December 1917.

With the continuing relatively  mild weather in December, there was no snow recorded.  The last time we saw any snow fall was more than a year ago, when 1 cm fell on November 29, 2014.  The last time we had more than 1 cm actually accumulate on the ground was January 20, 2012 - almost 4 years ago.

We experienced a lot of wind in Victoria in December, particularly during the first part of the month when there were a series of storms.  The peak wind was 104 km/hr gust on December 12.  Wind gusts topped 80 km/hr on three other days.

Year in Review: 2015

It's New Year's Day, a good time to review the weather we experienced in Victoria during 2015.

The most significant feature of the weather in 2015 was the warmth.  2015 was the warmest year on record at Victoria Gonzales, with the recording-keeping going back over 100 years to 1898.  The mean annual temperature was 11.7 degrees compared with the 1981-2010 average of 10.6 degrees.  The old record was 11.5 degrees in 2004.  Ten of the months during 2015 were warmer than normal - only September and November were below average.

Some months also broke temperature records.  February 2015 was by far the warmest February on record at Victoria Gonzales, with a mean temperature of 8.9 degrees and an average daily max/min of 11.2 / 6.6.  February was 2.4 degrees above the average of 6.5 and smashed the old record of 8.2 degrees by a wide margin.  In addition, June 2015 tied with June 2003 as the warmest on record, with a mean temperature of 16.1 degrees and an average daily max/min of 20.7 / 11.5.  Average mean temperature for June at Victoria Gonzales is 14.5.  The warmest month of the year was July, with a mean temperature of 17.6 degrees.  That makes it the third warmest July on record at Victoria Gonzales, after July 2004 (17.8) and July 1958 (17.7).  July 2015 also tied with August 1997 as the fourth warmest month on record at Victoria Gonzales.

Victoria also experienced its warmest summer on record in 2015, with a mean temperature of 16.9 degrees for June, July, and August combined compared with a normal summer temperature of 15.6 degrees.  The old record was 16.8 degrees in 2004.

The warmest temperature of the year was 31.3 degrees on July 30.  Despite 2015 being such a warm year on average, that date was the only time the temperature topped 30 degrees, compared with 5 days in 2004.  So 2015 was right on the average for Victoria Gonzales of 1 day with temperatures above 30.  We did get more than our usual number of days with temperatures above 25 degrees - 12 days compared with the average of 8.6 days.  The coldest temperature was -0.9 degrees reached on the very last day of the year - December 31.  There were just 4 days in 2015 when the overnight temperature dropped below freezing, compared with the normal 11 days.

2015 will also be remembered for the dry late spring and summer.  While summer drought is not in the least unusual in Victoria, this year was exceptional, particularly in the spring and early summer.  May 2015 was the driest on record at Victoria Gonzales, with just 1.8 mm of rain.  During the four month period from April 1 to July 31, just 24.6 mm of rain fell in Victoria compared with the usual 92.7 mm.  That makes it the driest April to July period on record in Victoria.

Despite this dry spell, above average rainfall during most of the rest of the year - especially during the last three months of the year - resulted in a wetter than average year with 735 mm compared with the average 641 mm.

Victoria recorded no snowfall during 2015.  This is the first calendar year since 1999 with absolutely  no snow.  Sometimes, Victoria will get a few snow flurries, even if it doesn't stick, but this year we didn't even get that.  With no snow falling,  Victoria continued its streak of winters with no snow accumulating on the ground.  The last time we saw at least 1 cm of snow on the ground was back in January 2012 - almost four years ago.

Victoria Gonzales Weather Summary for 2015
Month	Max	Min	Average	Rain	Snow
	° C	° C	° C	mm	cm
Jan	9.0	5.2	7.1	96.1	-
Feb	11.2	6.6	8.9	82.8	-
Mar	12.4	6.5	9.5	82.3	-
Apr	13.6	6.5	10.1	10.8	-
May	17.1	9.2	13.2	1.8	-
Jun	20.7	11.5	16.1	3.8	-
Jul	22.0	13.0	17.6	8.2	-
Aug	21.1	12.6	16.9	26.5	-
Sep	17.8	10.6	14.2	38.6	-
Oct	15.5	10.0	12.8	108.4	-
Nov	9.4	4.6	7.0	155.9	-
Dec	8.1	4.3	6.2	120.2	-
Annual	14.8	8.4	11.7	735.4	-