Thursday, February 28, 2019

A very cold February in Victoria!

A snowy Victoria Inner Harbour on February 12, 2019

February 2019 was the coldest February in Victoria since 1936.  The mean monthly temperature was just 2.2 C, more than 4 degrees colder than the 30-year average mean monthly February temperature of 6.3 C.  It's very unusual to have such a large anomaly for the mean monthly temperature in Victoria.  The average daily maximum temperature was 4.7 C, which is 4.1 degrees cooler than the normal February maximum of 8.8 C.  The average daily minimum temperature was -0.4 C, which was 4.2 degrees cooler than the normal February minimum of 3.8 C.  This is the first month since November 1985 that Victoria Gonzales has recorded an average minimum temperature below 0. 

Perhaps even more impressive, this past month was the coldest of any month at Victoria Gonzales since November 1985 (34 years).  In the past 50 years, there have only been two other months which have been colder than this February: November 1985 (1.8 C) and January 1972 (2.1 C).  

The coldest temperature this month was -5.6 C on February 4.  The warmest temperature was 9.0 C on February 1.  There were 13 days this month when the overnight low was below 0 C.  This is the most "frost days" in February at Victoria Gonzales since 1936, when there was 17 days.  What is most notable about the cold weather this month is how the temperatures have stayed consistently below normal since February 3.  With 26 consecutive days below normal in February, and the cool weather forecast to continue into March, this will likely be one of the longest stretches of below-normal temperatures recorded at Victoria Gonzales in the  past 50 years.

As the chart below shows, temperatures around the region were very cold in February, with many locations experiencing their coldest February in decades.  The mean monthly temperature was 2.2 C at Victoria Gonzales and 1.8 C at the University of Victoria. As is typical, the temperature was quite a bit colder at the Victoria Airport (1.1 C), which had its coldest February since 1989.  Vancouver Airport (0.4 C) had its coldest February on record (going back to 1937).  Seattle Airport (2.5 C) had its third coldest February on record, and its coldest since 1989.


Mean Monthly Temperature, February 2019

We can take some solace in the fact that these unusually cold temperatures have been experienced throughout much of western North America.  Calgary has also had its coldest February since 1936 (the same year Victoria experienced its coldest February).  Even Los Angeles has had its coldest February since 1962 (57 years).  

The chart below compares daily maximum and minimum temperatures with the 30-year average daily maximums and minimums.  Temperatures plummeted on February 3rd, and remained extremely cold for the remainder of the first half of the month, with high temperatures most days not even reaching the average low temperature.  The second half of the month was slightly less cold, though still below normal.  


Daily Maximum and Minimum Temperatures at Victoria Gonzales, February 2019


In terms of precipitation, February 2019 was somewhat drier than normal, with 46.2 mm of precipitation versus the 30-year average of 61.4 mm.  The unusual thing about this month was how much of this precipitation fell as snow.  A total of 26 cm of snow fell in Victoria during the month, making it the snowiest month since December 2008.  Normal February snowfall in Victoria is 3.6 cm.  There was measurable snow on the ground for 7 days during the month, including 5 days with more than 2.5 cm on the ground.  Victoria actually got off lightly, since many locations around the region received significantly  more snowfall, including 68 cm at the Victoria Airport in North Saanich.

The chart below shows daily and cumulative precipitation at Victoria Gonzales.  The precipitation from February 3rd to 14th all fell as snow.  The wettest day was February 11th, with 14.8 mm of precipitation, which translated into about 16 cm of snow.   The second half of the month was quite dry.

Daily and Cumulative Precipitation at Victoria Gonzales, February 2019



Sunday, February 10, 2019

The timing of winter in Victoria

The winter season can have different meanings, and its exact timing tends to vary from place to place.  Astronomical winter is from the winter solstice (roughly December 21) to the spring equinox (roughly March 21).  Meteorological winter is from December 1 to February 28. 

In Victoria, our winter (the coolest, cloudiest, and rainiest time of year) tends to come early.  On average, the coldest temperatures occur in late December.  By contrast, in most locations in the eastern half of Canada, the coldest temperatures of the winter tend to be in late January - a full month later.  The chart below shows the average daily maximum temperature in Victoria for astronomical winter (the blue line is the daily maximum temperature and the red line is a moving average weekly temperature to smooth out the trend).  You can see that temperatures tend to steadily increase throughout the winter, from about 6.5 C in late December to 11.5 C in late March. 

Average daily maximum temperatures in Victoria during the winter

Other aspects of Victoria's winter also tend to come early.  The rainiest month in Victoria is November, followed by December and January.  As we progress through the winter, it tends to get less and less rainy.  Victoria is most likely to receive snow in December, but the chances of snow decline later in the winter, particularly as we get into February.  December is the cloudiest month in Victoria, but sunshine starts to increase in January, then really increases in February and March. 

It's nice that we get the worst part of our winter over with in November and December, then we can look forward to gradually improving conditions after that!

Wednesday, January 2, 2019

2018 Year in Review

2018 was warmer and slightly drier than average in Victoria.

The mean temperature at Victoria Gonzales for 2018 was 11.0 degrees C, almost half a degree above the 30-year average of 10.6 degrees.  2018 was the 18th warmest year on record at Victoria Gonzales, going back 105 years.  The warmest year on record was 11.7 degrees in 2015.  It was also warmer than average at the Victoria Airport (10.7 degrees versus the average 10.1 degrees).  On the other hand, the  mean temperature at the University of Victoria was 10.9 degrees, which is slightly below its long term average of 11.1 degrees.

Ten of the twelve months had above normal temperatures, with only February and September being cooler than average in 2018.  While February 2018 was 1.2 degrees cooler than normal, both May and December were 1.2 degrees warmer than normal - the largest positive monthly anomaly in 2018.  July was a close third, being 1.1 degrees warmer than normal.

While 2018 was warmer than average, there were few extremely warm days during the year.  The warmest temperature was 27.2 degrees on August 14.  The warmest annual temperature at Victoria Gonzales is above 30 degrees roughly 50% of years.  The coldest temperature in 2018 was -2.2 degrees on February 21.  There were 7 days in 2018 when the temperature went below 0, compared with the long-term average of 9.5 days.

The chart below shows the daily maximum and minimum temperatures at Victoria Gonzales in 2018, compared with the long-term normal temperatures.  You can see the cold snap in late February, the unseasonably warm weather in May, as well as the generally warmer than average temperatures throughout the year.

2018 Daily Max & Min Temperatures at Victoria Gonzales

2018 was slightly drier than average in Victoria.  There was 594 mm of precipitation, 91% of the normal 654 mm.  Seven months were drier than normal.  Victoria typically experiences its driest weather in the summer months, and this year it was even drier than normal, with only 29 mm of rain from May to August, well under half the  normal 80 mm of rain for the period.

Thanks to its location in the Olympic Mountain rain shadow, Victoria receives less precipitation than surrounding locations, and 2018 was no exception.   The chart below compares annual precipitation in 2018 in locations around Victoria, Vancouver, and Seattle.  The Victoria Airport recorded 863 mm, 45% more than than the 594 mm at Victoria Gonzales.  The Seattle Airport received 908 mm of precipitation in 2018.  The Vancouver Airport recorded 1343 mm of precipitation while Vancouver Harbour recorded 1731 mm.  Interestingly, while locations in Victoria and Seattle were a bit drier than normal in 2018, the Vancouver locations were wetter than normal.  While Vancouver Harbour, on average, gets just under two and half times as much precipitation as Victoria Gonzales, in 2018 Vancouver got nearly 3 times as much.

Annual Precipitation in 2018


The chart below shows daily and cumulative precipitation at Victoria Gonzales in 2018.  You can see that the cumulative precipitation in 2018 (red line) fairly closely followed the long-term average trend (blue line).  Early spring was a little wetter than normal, followed by the dry summer.  Cumulative rainfall almost caught up to normal in November, but then fell slightly behind again by the end of the year.

2018 Daily & Cumulative Precipitation at Victoria Gonzales

There were 126 days with measurable precipitation in 2018, a little under the normal of 131 days.  The wettest day in 2018 was January 11, with 27 mm.  That was, in fact, the only day in 2018 with more than 25 mm of rain.  The long term average for Victoria Gonzales is 3 days per year with 25 mm or more precipitation.  There were 14 days with at least 10 mm of rain, compared with the  normal of 16 days.

Victoria had less snow than average in 2018, with 6 cm of snow, all of it recorded on February 21.  The long term average for Victoria is 21 cm of snow and 3 days with snowfall.  There was snow on the ground for 2 days compared with the long term average of 4.8 days.


Wednesday, December 12, 2018

Victoria's Fall of 2018: slightly warmer and drier than nomal

November 30 marked the end of meteorological fall (September, October, and November), so it's time to take a look back at the fall of 2018 in Victoria.  Overall, the summer was slightly drier and warmer than normal.  This was due to warmer and drier than normal conditions in October and November, since September was actually slightly cooler and wetter than normal.

Victoria received 186 mm of rain during the September to November period at Victoria Gonzales.  That's about 18% less than the 30-year average fall rainfall of 226 mm.  Rainfall was actually a bit above normal in September (28 mm in 2018 vs. the average 24 mm).  However, this was followed by a drier than average October (50 mm vs. 72 mm) and November (108 mm vs. 130 mm).  

There were 39 days with measurable precipitation this fall, with 11 days in September, 13 days in October, and 15 days in November.  That's actually slightly above the 37 days with measurable rainfall that Victoria typically receives during the fall (7 days in September, 12 days in October, and 19 days in November).  

The chart below shows daily rainfall during fall 2018, and compares the cumulative rainfall with the 30-year average.  September and early October were slightly wetter than normal.  This was followed by a two-week dry spell during the middle of October.  The end of October and beginning of November was the wettest period of the fall, with  nearly half of Victoria's fall rainfall this year being recorded over a 9-day stretch from October 27 to November 4.  This period included the wettest single day of the fall: 19.6 mm on November 1.  The remainder of November was a little drier than normal.


Daily & Cumulative Rainfall in Victoria, Fall 2018
The chart below compares the rainfall amounts in Victoria this fall with other locations in the regions.  As is typically the case, Victoria Gonzales had the lowest amount, with a total of 186 mm.  Victoria Airport had 280 mm mm of rain throughout the fall, about 50% more than Victoria Gonzales.  It was wetter still in Vancouver, with 425 mm at the Vancouver Airport and 552 mm at Vancouver Harbour - nearly 3 times what Victoria received.  By comparison, it was relatively dry in Seattle, with 260 mm.  That's less than Victoria Airport received, but still about 40% more rainfall than Victoria Gonzales.  

Fall 2018 Rainfall


The mean temperature this fall at Victoria Gonzales was 11.4 degrees, warmer than the 30-year average of 11.0.  Fall 2018 was tied for the 21st warmest in 105 years of record-keeping at Gonzales, so only about 1 in 5 falls have been warmer.  (Fall 1987 was the warmest on record, at 12.3 degrees.)  September 2018 was actually a bit cooler than average (14.3 degrees vs. the average 14.6).  However, both October and November were warmer than average.  In October it was 11.2 degrees vs. the average 10.9, while in November it was 8.7 vs. the average 7.5 degrees.  November was the 14th warmest on record at Victoria Gonzales (going back 105 years).  

The chart below shows the daily maximum and minimum temperatures at Victoria Gonzales during fall 2018, compared with the 30-year averages.  You can see that September was generally a bit cooler than average, while October and November were both a bit warmer than average.  The warmest day of the fall was 23.3 degrees on September 5, although it also reached 23.1 degrees on September 28, which was a greater anomaly from the average (which is 17.5 degrees for that date).  The coolest temperature was 2.7 degrees on November 19.


Daily Max & Min Temperatures in Victoria, Fall 2018

Sunday, September 2, 2018

Victoria's Summer of 2018: warmer and drier than average

August 31 marks the end of meteorological summer (June, July, and August), so it's time to take a look back at the summer of 2018 in Victoria.  Overall, the summer was drier and warmer than normal.

Victoria has dry summers, averaging just 52 mm of rain during the June to August period at Victoria Gonzales.  This year, summer was particularly dry, with just 21 mm of rain.  That makes it the 8th driest summer in the past 105 years.  (The driest summer on record was 1970, with just 10.5 mm of rain.)  In 2018, rainfall in June was actually close to average (18.6 mm vs. the average 20 mm), but that was followed by an extremely dry July and August.  There was no rainfall recorded at Victoria Gonzales during July (the sixth time that has happened).  August was also very dry, with just 2.0 mm of rain (all of which fell during a one-hour rainshower on August 11).  August 2018 was the 13th driest on record at Victoria Gonzales, so only about 1 in 8 Augusts have been drier.  This year is notable because the combined July-August rainfall of 2.0 mm was the lowest on record.  Interestingly, the second driest July-August on record was 2017, with 2.2 mm, so we have experienced back to back records for dry July-August periods.

There were 8 days with measurable precipitation this summer, with 7 of those days falling in June.  Victoria typically receives 15 days with measurable rainfall during the summer month (7 in June and 4 each in July and August).  

The chart below shows daily rainfall during summer 2018, and compares the cumulative rainfall with the 30-year average.  June was fairly typical in terms of rainfall, but that was followed by a 41-day stretch with no measurable rainfall from July 1 to August 10.   That's a little longer than the typical drought period that Victoria receives each summer, which averages 28 days.  The only rainfall during the July-August period came during a one-hour rainshower on August 11.  After that, there was no measurable rainfall for the remainder of the month.


Daily & Cumulative Rainfall in Victoria, Summer 2018
The chart below compares the rainfall amounts in Victoria this summer with other locations in the regions.  As is typically the case, Victoria Gonzales had the lowest amount, with a total of 20.6 mm.  Victoria Airport had 27.4 mm of rain throughout the summer, about one third more than Victoria Gonzales.  Although this summer was also drier than normal in Vancouver, it still had about 3 times as much rainfall as Victoria (67 mm at Vancouver Harbour), which is pretty typical.  Rainfall in Seattle was also well below average this summer, and it received just slightly more rain (22.4 mm) than Victoria.   June accounted for the majority of rainfall this summer in all locations.  If you look at just July and August, the difference between Victoria and the other locations is even more stark.  Victoria Gonzales received 2 mm of rain during July and August versus about 6 mm in Seattle and 20 mm in Vancouver.  


Summer 2018 rainfall by month

The mean temperature for June, July, and August at Victoria Gonzales was 16.0 degrees, warmer than the 30-year average of 15.6.  Summer 2018 was tied for the 13th warmest in 105 years of record-keeping at Gonzales, so only about 1 in 8 summers have been warmer.  (Summer 2015 was the warmest on record, at 16.9 degrees.)  June's mean temperature of 14.5 degrees was right on the average.  July's mean of 17.1 degrees was a full degree above the average while August's mean of 16.5 degrees was just 0.2 degrees above average.  This summer, and especially this July, was considered a hot one in Victoria.  However, Victoria Gonzales didn't really experience any extremely hot temperatures.  The warmest maximum during the summer was just 27.2 degrees on August 14 (and the warmest Victoria Gonzales reached in July was just 26.4 degrees).  In fact, the hottest day of the summer this year (27.2) was the 10th coolest on record at Victoria Gonzales, and the coolest since 1982 (that's 36 years).  Typically, the warmest day of the summer at Victoria Gonzales is around 30 degrees.

The chart below shows the daily maximum and minimum temperatures at Victoria Gonzales during summer 2018, compared with the 30-year averages.  While daytime highs during the first half of June were cooler than average, the rest of the summer was mostly above average, though as noted above, there were no extremely warm temperatures.  Overnight lows were quite consistently close to average or slightly warmer than average.


Average daily max & min temperatures in Victoria, Summer 2018

Saturday, August 4, 2018

A warm and dry July in Victoria

July is typically the driest month of the year in Victoria, and this year it was particularly dry: there was no  measurable rainfall recorded at Victoria Gonzales during the entire month.  This is actually the 6th rain-free July at Victoria Gonzales, the others being 1914, 1922, 1926, 1958, and 1984.  There have also been another 6 Julys with less than 1 mm of rain recorded.

It was a dry month throughout the region, but most other locations outside Victoria recorded at least some rain, including the University of Victoria (0.9 mm), the Victoria Airport (2.2 mm), Vancouver Airport (5.4 mm), Vancouver Harbour (14.2 mm), and Seattle (1.3 mm).

July was also warmer than average in Victoria.  The mean temperature of 17.1 was more than a full degree above the 30-year average of 16.0, and it tied for the 7th warmest July at Victoria Gonzales.    The warmest July was 17.8 degrees in 2004.  The average daily maximum/minimum temperatures for July 2018 were 21.8/12.4 compared with the normal 20.4/11.7.  Although there was a lot of talk about an extended heat wave in the region this July, it never really got that hot along the water in Victoria.  The warmest temperature recorded at Victoria Gonzales for the month was 26.4 degrees, which is below the average monthly maximum temperature for July of 27.9 degrees.

Temperatures were considerably warmer in other parts of the region.  The mean temperature at the Victoria Airport was 18.3 degrees ( with a daily max/min of 24.3/12.4).  At the University of Victoria, the July mean temperature was 18.6 (25.5/11.7).  The table below shows the average daily maximum temperature for July 2018 at a number of locations around the region.  The official Environment Canada weather stations are bolded; the other stations are from the Victoria Schoolnet weather stations.  Average temperatures ranged from a cool 19 degrees at Trial Island lightstation (just off south Oak Bay) to a toasty 27.5 degrees at Butchart Gardens, near Brentwood Bay in Central Saanich. 

Average Daily Maximum Temperature - July 2018



Friday, August 3, 2018

Canadian Climate Comparison: What are the sunniest cities in Canada?

After comparing temperature and precipitation in the 41 largest urban areas in Canada (those with at least 100,000 population), we'll now look at sunshine.

The chart below ranks the average annual hours of sunshine in the 41 largest cities in Canada, from highest to lowest.  The 7 sunniest cities are all located in the southern Prairies, but with 2,198 annual hours, Victoria comes in a very respectable 8th place out of the 41 cities.  Put another way, Victoria gets more sunshine than 82% of Canada's urban population.

Victoria is by far the sunniest of the British Columbia cities included in the ranking: Kamloops, the next sunniest B.C. city, ranks 16th out of 41, while Kelowna in the "sunny Okanagan" ranks 28th.  The other coastal B.C. cities are all near the bottom of the ranking, taking up the 37th through 40th spots.  Only St. John's Newfoundland ranks lower in terms of annual sunshine.  The difference between Victoria and the other coastal B.C. cities is striking, and again points to the importance of the Olympic Mountain rainshadow in impacting Victoria's climate.

Average Annual Sunshine Hours for Urban Areas in Canada
As with precipitation, seasonal variations are also important in comparing Canadian cities.  The chart below ranks summer (June to August) sunshine hours in Canadian cities.  Victoria moves up to rank as the third sunniest summer, after Lethbridge and Regina.  Victoria has sunnier summers than 97% of Canada's urban population.  Though well behind Victoria, the other coastal B.C. cities fare better on summer sunshine than they do on annual sunshine, with Nanaimo in 24th and Vancouver in 29th.  Cities in Atlantic Canada hold the bottom 4 spots.

Average Summer Sunshine Hours for Urban Areas in Canada

In addition to having the 3rd sunniest summers among Canadian cities, Victoria ranks as the 8th sunniest for both springs and falls.  Winter, however, is quite different.  The chart below ranks winter (December to February) sunshine hours for Canadian cities.  The top 10 sunniest winter cities include a mix of cities in the Prairies, as well as New Brunswick and Quebec.  Victoria ranks a lowly 33rd, although that is still better than any of the other B.C. cities, which fill the bottom 6 spots.  It might surprise some that Kelowna - in the "sunny Okanagan" - has the cloudiest winters among Canadian cities, but B.C.'s Interior valleys are very prone to low cloud and fog in the winter.   

Average Winter Sunshine Hours for Urban Areas in Canada