After wild fluctuations, winter 2023-24 was slightly milder then normal

 Meteorological winter is from December 1 to February 29.  Winter 2023-24 was colder and drier than normal.  

The mean temperature at Victoria Gonzales this past winter was 6.5 degrees C, compared with the 30-year average of 5.8 C.  The average daily maximum temperature was 8.5 C (versus normal 7.9 C), while the average daily minimum was 4.5 C (versus the normal 3.7 C).  December was much warmer than average.  January was slightly colder than average, while February was slightly milder than average.

The chart below shows the daily maximum and minimum temperatures at Victoria Gonzales during winter 2023-24, compared with the 30-year averages.  The cold snap in mid-January really stands out, with temperatures far below normal. The temperature dropped as low as -11.5 C on January 12, the coldest temperature recorded in Victoria in 55 years (since December 1968). 

Despite the cold snap, there was also some warm weather.  December 2023 was tied with December 1939 as the warmest on record in Victoria, with a mean temperature of 7.7 C, more than 2 degrees above the 30-year average.  There was also an extraordinary mild period at the end of January, when a Pineapple Express atmospheric river brought warm subtropical air into the region.  The 5-day period from January 28 to February 1 was the mildest 5-day period ever recorded during the winter in Victoria.  The mean temperature was 11.8 C, and highs exceeded 15 C on January 29 & 30.  There were also 3 days with overnight lows above 10 C - by far the earliest that has ever occurred in Victoria.  The previous earliest occurrence was March 12. 

Winter 2023-24 saw very close to normal precipitation.

The chart below shows daily precipitation during winter 2023-24, and compares the cumulative precipitation with the 30-year average.  Precipitation tracked close to average throughout the winter.  December and February were both slightly drier than normal, while January was slightly wetter than normal.  The wettest day of the winter was December 4th, when 19.4 mm fell.  

While precipitation was average, the number of days with measurable precipitation was above average: 51 days during winter 2023-24 vs. the 30-year average of 46.3 days.

Winter 2023-24 saw less snow than normal.  There was 8.5 cm of snow compared with the normal 14 cm.  All of the snow was recorded in January.  There were 3 days with at least 2 cm of snow on the ground - close to the 30-year average of 3.2 days for the winter.

Summer 2023: warmer and slightly drier than normal

 Meteorological summer consists of June, July, and August.  Summer 2023 was warmer and a bit drier than normal.

The mean temperature this past summer at Victoria Gonzales was 16.4 degrees, which is 0.7 degrees above the 30-year average.  Summer 2023 was tied for the 6th warmest in Victoria since record-keeping began at Gonzales Observatory in 1914.  Temperatures got warmer as the summer progressed: June was close to average, July was 0.5 degrees above normal, and August was 1.4 degrees above normal.  In fact, August's mean temperature of 17.8 C was the warmest on record at Victoria Gonzales.

The average daily high temperature this summer was 20.7 C (versus the normal of 20.0 C) while the average daily minimum was 12.0 C (normal 11.5 C).   

The chart below shows the daily maximum and minimum temperatures at Victoria Gonzales during summer 2023, compared with the 30-year averages.  The first half of the summer had a mix of both below and above normal temperatures, while the second half of the summer saw mostly above normal temperatures.  The warmest temperature of the summer was 32.5 C on August 19th, which was also the 10th hottest August day ever recorded in Victoria.  It was the only day of the summer to exceed 30 C.    

The coolest temperature during the summer was 8.5 C on June 19th.

Daily Max & Min Temperatures in Victoria, Summer 2023

Victoria received 35.4 mm of rain from June to August, about three-quarters of its normal summer rainfall of 47 mm. While it was drier than normal, it was not usually so: summer 2023 was just the 41st driest summer in Victoria in the 125 years of record-keeping.  Just two days accounted for 70% of the summer's rainfall: June 10th (13.2 mm) and July 24th (11.4 mm).

Victoria had only 8 days with measurable rainfall this summer, compared with the normal 14.8 days.  There were 3 days with measurable rain (>0.2 mm) in June, 1 in July, and 4 in August.  

The chart below shows daily precipitation during summer 2023, and compares the cumulative precipitation with the 30-year average.   While rainfall was very sporadic, the cumulative rainfall generally kept fairly close to normal throughout the summer.

Daily & Cumulative Rainfall  in Victoria, Summer 2023

Summer 2023 sunnier than normal.  June and July were both sunnier than normal, while August was close to normal.  

The table below shows the number of mostly sunny days (>80% of possible sunshine), partly cloudy days (20-80% of possible sunshine), and mostly cloudy days (<20% of possible sunshine).  Summer 2023 was very sunny, with significantly more mostly sunny days than normal (62 in 2023 compared with the normal of 45 days).  There were also fewer mostly cloudy days than normal (10 days compared with the normal of 12).  July was a particularly sunny month.

Victoria's summer weather depends a lot on how close you are to the Strait of Juan de Fuca

 July 2023 was a very nice month in Victoria.  The temperature was above normal, with a mean temperature of 16.7 C at Victoria Gonzales, 0.5 degrees above normal.  With no significant heat waves, the extreme max at Victoria Gonzales was 26.4 C.  So it was warm, but not too hot.  Rainfall was close to normal (11.4 mm vs normal of 12.1 mm), but it all fell on one day (July 24), while the rest of the month was dry and mostly sunny.

However, Victoria has a lot of microclimates.  During the summer, the biggest factor is how close you are to the cool waters of the Strait of Juan de Fuca.  Locations near the Strait are much cooler and windier than other parts of Greater Victoria.

Below is a table showing the average daily maximum temperature during July for various Environment Canada weather sites in Greater Victoria.  While locations near the Strait (Victoria Harbour, Victoria Gonzales, and Esquimalt Harbour) averaged 20-22 C, other locations were in the 24-26 C range.

This table doesn't even capture the full impact of the Strait.  The numbers in the table are calculated by averaging the high temperature for each day in July.  However, places near the Strait often only hit their daily high for a brief period before the seabreeze kicks back in again, while locations away from the Strait tend to see more extended periods of warmer temperatures in the afternoon.

The chart below compares the average hourly temperature at Victoria Gonzales and at the University of Victoria.  While the average temperature at U-Vic warms steadily throughout the afternoon, peaking just below 24 C, the average temperature at Victoria Gonzales remains close to 18 C all afternoon.

Wind is another major difference.  The chart below compares the average hourly wind speed at Victoria Gonzales and at the University of Victoria.  At Gonzales, the wind is generally light in the morning, but it tends to build during the afternoon, and peaks at an average 24 km/hr in the early evening hours between 6 pm and 9 pm.  By contrast, winds are much lighter at UVic, peaking at only 7-8 km/hr during the afternoon.

These differences can mean that people in different parts of Greater Victoria can experience very different summers, depending on where they live.  For those in the southern part of Esquimalt, James Bay, Fairfield, and South Oak Bay, summers are much cooler and breezier than they are elsewhere.

Spring 2023 was dry and sunny, with overall normal temperatures

 Meteorological spring is from March 1 to May 31.  Overall, spring 2023 saw close to normal temperatures, but was much drier than normal.  

The mean temperature at Victoria Gonzales this past spring was 10.1 degrees, which is right on the 30-year average.  The average daily maximum for spring 2023 was 13.6 degrees , while the average daily minimum was 6.5, again both very close to the 30-year averages.  This masked some significant differences during the season.  March was 0.6 degrees C below normal, while April was a chilly 1.2 degrees C below normal.  That contrasted with May, which was the warmest May on record at Victoria Gonzales, a full 1.7 degrees C above normal.

The chart below shows the daily maximum and minimum temperatures at Victoria Gonzales during spring 2023, compared with the 30-year averages.  Temperatures during March were fairly close to normal, then during April they fell significantly below normal.  There was a spike in temperatures in late April, with temperatures getting into the low 20s, then an even bigger spike in mid-May, with temperatures reaching the low 30s.  Temperatures remained above normal for most of May.  The warmest temperature was 30.7 C on May 14.  In fact, this was the second highest temperature ever recorded at Victoria Gonzales in May.  The coldest temperature was 0.4 C on March 1.  There were no days below freezing during spring 2023.  Normal is 0.7 days.

Daily Max & Min temps vs 30-yr normal, Spring 2023

Following a drier than normal winter, Victoria experienced a dry spring in 2023.  There was 58.4 mm of rain, just over half of the normal 115.4 mm 

There were just 22 days with measurable rainfall during spring 2023, compared with the normal of 33 days.  There were 8 days in March (normal 14.5), 11 days in April (normal 10.3), and 3 days in May (normal 8.4).  The wettest day was May 5, when 12.4 mm of rain fell.

The chart below shows daily precipitation during spring 2023, and compares the cumulative precipitation with the 30-year average.  Precipitation tracked below average throughout the spring.  

Overall, spring 2023 was sunnier than normal.  March saw more sun than normal, while April saw less.  However, May was likely one of the sunniest Mays on record in Victoria, with an estimated 335 hours.  The official record is 356.4 hours from May 1963.  There were 40 mostly sunny days during spring 2023, including 22 mostly sunny days in May.

A strong rainshadow and a dry April

Victoria is often in the rainshadow of the Olympic Mountains, and as a result it generally gets much less rain than surrounding areas.  This phenomenon was really on display in April.

Below is the radar image for April 6, 2023.  The rainshadow "hole", to the northeast of the Olympic Mountains is clearly visible.  

Here is another radar image from April 6, showing a closer view of Victoria.  A great rainshadow, extending across Greater Victoria, the San Juan Islands, and over towards Anacortes.

Southwestern B.C. and the US Pacific Northwest experienced an atmospheric river event from April 6-9, 2023.  However, the rainshadow kept Victoria extraordinarily dry.  Below is a chart comparing the rainfall totals for April 6-9.  Rainfall in the core area of Greater Victoria ranged between 0.8  and 2 mm.  Victoria Airport (located 25 km to the north and typically less protected by the rainshadow) received 8.3 mm.  Other locations in the region received 25 mm or more, including 64 mm at Vancouver Harbour and 77 mm at West Vancouver - nearly 100 times as much rain as the University of Victoria received.

While the April 6-9 event was the most dramatic, Victoria stayed significantly drier than other locations in the region for the whole month.  The chart below compares April rainfall totals.  Again, locations in the core area of Greater Victoria were much drier, receiving between 17.8 mm and 22 mm of rain for the entire month (normal April rainfall for Victoria Gonzales is about 34 mm).  The Victoria Airport and the Cowichan Valley each received more than 3 times as much rain as Victoria Gonzales.  Seattle received more than 5 times as much rain as Victoria, and Vancouver Harbour received nearly 9 times as much rain.   Port Alberni and West Vancouver received 11-12 times as much rain as Victoria Gonzales.

April continued the trend of a dry start to 2023.  During the first 4 months of the year, Victoria Gonzales has only received about 128 mm of precipitation - half of the normal 257 mm for that period.

Winter 2022-23 was colder and drier than normal

Meteorological winter is from December 1 to February 28.  Winter 2022-23 was colder and drier than normal.  

The mean temperature at Victoria Gonzales this past winter was 4.9 degrees C, compared with the 30-year average of 5.8 C.  The average daily maximum temperature was 7.0 C (versus normal 7.9 C), while the average daily minimum was 2.8 C (versus the normal 3.7 C).  December was much colder than average.  January was slightly milder than average, while February was colder than average.

The chart below shows the daily maximum and minimum temperatures at Victoria Gonzales during winter 2022-23, compared with the 30-year averages.  The cold snap in late December really stands out, with temperatures far below normal. The temperature dropped as low as -9.5 C on December 22, the second December in a row with a very strong cold snap and very low temperatures. January temperatures were a bit above normal, but February temperatures once more fell below normal.

Daily Max & Min temps vs 30-yr normal, Winter 2022-23

Winter 2022-23 was drier than normal, with 197 mm of precipitation versus the normal of 266 mm. Precipitation was a bit above normal in December (114 mm vs. 98 mm), but January was very dry (26.3 mm vs. normal 104.3 mm), and February was also slightly drier than normal (57.1 mm vs. normal 63.5 mm).

The chart below shows daily precipitation during winter 2022-23, and compares the cumulative precipitation with the 30-year average.  Precipitation tracked close to average during the first part of the winter, but fell below average in January.  

Winter 2022-23 was also much snowier than normal.  There was 41 cm of snow compared with the normal 14 cm.  Nearly all of the snow (37 cm) fell in December.  

Victoria's weather in 2022

 

After a year of extremes in 2021 (including the hottest temperature on record and the most annual precipitation on record), 2022 was not quite so extreme.

The mean temperature for 2022 (10.5 C) was slightly below the 30-year average of 10.7 C, while the annual precipitation of 658.5 mm was very close to the average of 656 mm.

Victoria experienced the warmest late summer/early fall on record in 2022.  August and October were both the warmest on record, while September was the second warmest. Overall, the August to October period was 1.7 degrees warmer than the 30-year average.  

March, June, and July were slightly above normal.  The remaining six months were all below normal temperatures.  In particular, April-May was 1.8 degrees below normal and November-December was 2.1 degrees below normal, making for a cold spring and a very cold late fall/early winter.

The hottest temperature of 2022 was 30.9 degrees on June 26.  There were 2 days in 2022 with daily maximums above 30 C, compared with the normal of 1.1 days.  There were 18 days with daily maximums above 25 degrees, double the average of 9.1 days.    

The coldest temperature of 2022 was -9.5 C on December 21.  For the second winter in a row, Victoria experienced a significant cold snap in 2022, with 4 consecutive days below freezing.  Prior to 2021, Victoria hadn't experienced such a long cold snap for 36 years (since November 1985).  There were 19 days in 2022 when the temperature went below 0, significantly higher than the long-term average of 9.5 days, and the most since 1996.  Of those days when temperatures dropped below freezing, 12 occurred in November and December.

The chart below shows the daily maximum and minimum temperatures at Victoria Gonzales in 2022, compared with the long-term normal temperatures.  The chart shows a cold snap in late February, and the cool spring, with highs consistently below normal from mid-April to the end of May.  This was followed by a short heat wave in late June, then fairly consistently above-average temperatures from August to October.  There was an abrupt shift to below normal temperatures in November and December, culminating in the severe cold snap in late December.

The chart below shows daily and cumulative precipitation at Victoria Gonzales for 2022.   The thing that really stands out is the extraordinary 3-month dry spell from July 19 to October 20. During that period there was just 0.6 mm of rain recorded at Victoria Gonzales, making it the driest 3-month period on record, not just for Victoria, but likely for any major Canadian city.  The remainder of the year saw 3 wet periods (October 21-November 8, November 22-30, and December 17-31).  These were separated by two unusually dry spells for what is typically the wettest time of year in Victoria: just 2 mm of rain over weeks from November 9-21 and just 12 mm during the first half of December.

There were 124 days with measurable precipitation in 2022, compared with the normal of 132 days.  The wettest day was October 30th, with 40.6 mm of rain.  There were 4 days with more than 25 mm of rain in 2022, a little above the average of 2.9 days annually.  

The chart below compares annual precipitation at Victoria Gonzales in 2022 with other locations in the region.  Thanks to its rainshadow location, Victoria is typically drier than most other locations, and that was the case once again in 2022.  However, while Victoria's annual precipitation was close to the 30-year average, it was below average at the Victoria Airport (90% of normal) and Vancouver (89% of normal), but slightly above normal in Seattle (103% of normal).  

2022 Annual Precipitation vs normal

Victoria received 54 cm of snow in 2022, more than triple the average of 16 cm, and the most snow in a calendar year since 1996.  (2021, with 44 cm of snow, was the second snowiest year in Victoria since 1996.) 

How much and how often does it snow in Victoria?

Victoria gets less snow than any other city in Canada.  The 30-year (1991-2020) average annual snowfall for Victoria is 16 cm.  That's significantly less than nearby Vancouver, which receives an annual average of 34 cm, as measured at the Vancouver Airport.  

The core area of Greater Victoria also gets significantly less snow than outlying areas such as Langford or the Saanich Peninsula.  The Victoria Airport, located 25 km north of Victoria, averages 34.8 cm of snow annually - more than double what the City receives.  It's quite common for there to be snow in the Westshore or the Saanich Peninsula, while there is little or no snow in the core area.  This is due to the generally milder temperatures near the Strait of Juan de Fuca and the lower precipitation amounts in the core thanks to the Olympic Mountain rainshadow.

The table below summarizes the average snowfall and snow cover (days with at least 2 cm of snow on the ground) in Victoria, by month.  December has the highest amount of snowfall (6.3 cm), although both December and January have on average, a similar number of days with snow on the ground (1.2-1.3 days).

While the table above shows the 30-year averages for snow in Victoria, there is a lot of variability from year to year.  The chart below shows the annual winter snowfall over the past century.  The chart shows 3 years (1949/50, 1968/69, and 1996/97) when Victoria received more than 100 cm of snow.  In fact, the snowiest winter on record for Victoria was 1915/16 (not shown on the chart) when Victoria received an astonishing 195.6 cm of snow!  On the other hand, there have been 7 winters in the past 125 years (6%) with no snow, and 33 winters (26%) with less than 5 cm of snow.  

The chart also shows the rolling 30-year average snowfall and 30-year median snowfall (starting with the 30-year period from 1898/99 to 1927/28 and finishing with the most recent 30-year period of 1993/94 to 2022/23).  Because the average snowfall tends to be skewed by the occasional large snowfall, the median snowfall (11.5 cm for 1991-2020) is lower than the average snowfall (16.0 cm). 

Even the 30-year average snowfall has fluctuated significantly over time.  From a low point of 19.9 cm for 1918/19 to 1947/48, the 30-year average snowfall reached a high point of 37.5 cm for 1946/47 to 1975/76.  Since then, average snowfall has generally been decreasing, with climate change likely contributing to this trend.  For the most recent 30-year period (1992/93 to 2021/22), snowfall averaged 17.4 cm (slightly higher than the 1991-2020 average).  

The chart below shows the trend in number of days annually with at least 2 cm of snow on the ground.  Snow on the ground has only been measured in Victoria since 1955, so the period of record is shorter.  As with snowfall totals, the days with snow on the ground varies considerably from year to year.  In 19 of the past 68 winters (28%), there have been no days with 2 cm or more snow on the ground.  On the other extreme, there have been 4 winters with more than 15 days with snow on the ground - including one winter (1968/69) when there was 30 days with snow on the ground!  The average number of days with snow on the ground has generally decreased over time, from about 5 days for the 1955/56 to 1984/85 period down to about 3.8 days for the most recent 30-year period (1992/93 to 2021/22), which again was slightly higher than the 1991-2020 average.

Another way to look at the snowfall data is to use quintiles.

• The bottom quintile (the 20% of winters with the least snowfall) had an average snowfall of 1.2 cm and 0 days with snow on the ground.

• The next quintile averaged 7.3 cm of snow and 0.7 days with snow on the ground.

• The middle quintile averaged 16.5 cm of snow and 3.0 days with snow on the ground.

• The next quintile averaged 30.3 cm of snow and 5.4 days with snow on the ground.

• The top quintile (the 20% of winters with the most snowfall) had an average of 73.9 cm of snow and 15.2 days with snow on the ground.

You sometimes here about a big snow storm in another city dumping "a month's worth of snow" in a day or two.  Because snow is so infrequent in Victoria, it's not only very common to get a month's worth of snow all at once, but it's also common to get a full season's worth of snow in one storm.  For example, over the past 30 years, Victoria has received 76% of its total winter snowfall in a single two-day period.  During nearly one third of those years, Victoria received more than 95% of its seasonal snowfall in a single storm.

Other locations in the region have also seen a decline in average snowfall over the past few decades.  The chart below compares the trend in 30-year average snowfall in Victoria with other nearby locations (starting with the 30-year period from 1941/42 to 1970/71 and ending in the most recent 30-year period of 1993/94 to 2022/23).  All the locations have declined over this period.  Average snowfall levels in Victoria have trended quite closely to the pattern for Seattle.  By contrast, the Victoria Airport (in North Saanich) and the Vancouver Airport have significantly higher average snowfall levels, but they have also followed a declining trend.  

An extraordinary drought

 Victoria is known for its summer droughts.  It is the driest major city in Canada - by far - during the summer months, with an average of 47 mm of rain during June to August combined.  It is also common to get long stretches with little or no rainfall during the summer.  On average, Victoria gets 31 consecutive days with no measurable rainfall each summer, and 42 consecutive days with less than 1 mm of rainfall.

However, the past three months have really been extraordinary.  From July 19 to October 20 - a period of 94 days - there have only been 3 days each with just a barely measurable 0.2 mm of rain (August 10, September 4, and September 28) at Victoria Gonzales.  That's a total of just 0.6 mm of rain in the past 3 months!  The nearby weather station at the University of Victoria has been even drier, with just 0.4 mm of rain over the same period.

This has been the driest 90-day period ever recorded at Victoria Gonzales, as shown in the chart below, easily beating the old record of 2.8 mm, from May 25 to August 22, 1951.  Note that most of these record dry periods tend to be centered on July and August, the two driest months in Victoria.  However, 3 of the 11 driest periods, include this year's, have extended into mid-October.

This record-breaking drought has not just impacted Victoria; it has affected all of southwestern B.C.  The chart below shows the total rainfall for various locations in southern B.C. over the past 3 months. As is often the case, Victoria has been the driest location, but most locations have been extraordinarily dry.  Keep in mind, that normal rainfall during this period is 91 mm at Victoria Gonzales and 231 mm at Vancouver Harbour.  

Not only has this period been the driest 3-month period ever recorded in Victoria (with 120 years of record-keeping at Victoria Gonzales), but it is also likely the driest 3-month period ever recorded in any major Canadian city.  The driest 3-month period ever recorded for some other Canadian cities includes 1.3 mm for Edmonton, 2.9 mm for Calgary, 6.1 mm for Vancouver Airport, and 37.9 mm for Toronto

In addition to being dry, it has also been a very warm 3 months.  The chart below shows the daily maximum and minimum temperatures at Victoria Gonzales during the drought period (July 19 to October 19), compared with the 30-year average.  With just a few exceptions, temperatures have been above normal.  The average daily maximum temperature for the period was 21.3 C -  nearly 3 degrees above the historical average of 18.4 C.  In addition, the average daily maximum temperature for the period in 2022 (21.3 C) is more than 1 degree warmer than the previous highest average maximum of 20.1 C for the same period in 1998.

Victoria Gonzales Daily Max & Min vs. normal

Victoria records 53 days with no measurable rainfall - the third longest such dry streak on record

 Following the unprecedented heat wave in late June 2021, temperatures in Victoria returned to normal, but the dry sunny weather continued.  

Victoria Gonzales received no measurable rainfall in July.  That is the 7th time that Victoria has experienced a July with no measurable rain (the other times being 1914, 1922, 1926, 1958, 1984, 2018).  It is also the 12th time overall that Victoria has had a calendar month with no measurable rain.  

In all, there was no measurable rain recorded at Victoria Gonzales from June 15 to August 6 - a total of 53 days.  That makes it the third longest such dry streak recorded in Victoria over the past 120 years.  The longest dry streak was 63 days, from June 15 to August 16, 1926.  The second longest was 54 days from July 17 to September 8, 1986 - many residents will remember that year for the great weather at Expo 86.  

The chart below shows the longest dry streaks ever recorded in Victoria.  Of note, 4 of the 10 longest dry streaks occurred in the 1920s, which was the driest decade on record in Victoria for both average annual precipitation (601 mm) and average summer rainfall (34 mm for the June to August period). The past 10 years (2011-20) was the second driest decade for summers, with an average 36 mm of rain, which could indicate the beginning of a trend towards even drier summers that most climate models predict for our area as a result of climate change.  Conversely, none of the longest dry streaks was in the 1990s, which was one of the wettest decades (along with the 1930s) in Victoria, for both total annual precipitation and summer rainfall.  

Heat Wave June 2021: Victoria breaks its all-time high temperature record

The heat wave that Victoria and the surrounding region just experienced was truly historic.  Weather historian Christopher Burt described it as “the most anomalous regional extreme heat event to occur anywhere on Earth since temperature records began" roughly 150 years ago with the beginnings of modern meteorology.  Never before have so many all-time temperature records been broken by such a large margin in one region by a single event.  According to international weather records researcher Maximiliano Herrera, more all-time heat records were broken by at least 5 C in the June 2021 heat wave than in the previous 84-plus years of world weather recordkeeping.  A group of international climatologists estimated that this heat wave was a 1 in 1,000 year event for our region, and that even with continued climate change, it will remain a very rare event.

On June 28, 2021, Victoria recorded its all-time maximum temperature: 39.8 C.  That completely shattered the old record of 36.0 C set on July 11, 2007.  Many other locations in B.C., Washington, and Oregon also broke new all-time maximum temperature records.

Below are the June 25-29 daily high temperatures around the Victoria region:

The numbers are extraordinary.  Most locations broke their all-time temperature record on June 27, then broke it again on June 28.  Typically, when an all-time temperature record is broken, it might be by a fraction of a degree.  In this case, Victoria Gonzales beat its old record by 3.8 degrees, while Victoria Airport beat its old record by 3.1 degrees.  

The chart below shows hourly temperatures at Victoria Gonzales during the heat wave, compared with the average daily maximum and minimum temperatures in late June.  The peak temperature of 39.8 C at about 3 pm on June 28th was nearly 20 degrees C above the average!  Even the overnight lows on June 26th and 27th were higher than the average daily maximums.  

Some specific patterns are notable:

On June 26th, an on-shore sea breeze developed in the late morning and early afternoon that prevented temperatures at Gonzales from getting really hot.  The temperature peaked at 32.5 C between 11 am and noon, but then plunged to 23.4 C by 1 pm as the sea breeze kicked in.  

A sea breeze also developed on June 27th, but much later in the day.  The temperature peaked at 38.3 C between 2 pm and 3 pm.  It was still 35.9 C at 6 pm, but then a sea breeze developed and the temperature plunged 10 degrees in an hour, to reach 26.2 C at 7 pm.

The late evening, overnight, and early morning period between June 27th and 28th was remarkably warm.  After the early evening sea breeze on June 27th, the temperature warmed again, and was still a remarkable 28 C at midnight.  For most of the night, the temperature remained above 24-25 C, with just one hourly recording at 4 am  when the temperature dropped to 22.1 C.  By 7 am, the temperature was back up to an amazing 29 C, and it continued to increase sharply from there.

Also of note is the dramatic fall in temperatures on the evening of June 28th.  After hitting its peak of 39.8 C around 3 pm, the temperature remained a very hot 37.4 C at 6 pm, but then fell to 15.6 C at 6 am on June 29th - a drop of nearly 22 degrees C in 12 hours.  By the morning of June 29th, the heat wave was a distant memory, with a 10 am temperature of 16.2 C compared with 34.8 C at 10 am on June 28th.  That's a remarkable 18.6 degree C temperature change in 24 hours!  

In addition to these official Environment Canada weather stations, victoriaweather.ca (operated by University of Victoria climatologists) has a more extensive network of weather stations in the region.  Roughly 20 of these sites topped 40 C on June 28.  The table below shows the hottest of these in each municipality:

The chart below shows the annual maximum temperature at Victoria Gonzales over the past 120 years. The new record maximum set this year clearly stands out!

This next chart looks at the peak temperature for just the 10 hottest heat waves ever recorded at Victoria Gonzales:

Again, the June 2021 heat wave clearly stands out as something extraordinary.  All the previous heat records were in a fairly narrow band between 33 C and 36 C, while the extreme heat we just experienced was nearly 4 degrees higher!

As a result of the heat wave, June 2021 ended up being the warmest June on record at Victoria Gonzales.  If you look at the period from June 1 to June 24, prior to the heat wave, the mean temperature was 14.8 C, which was warmer than the 30-year average of 14.3 C, but not unusually so - the mean temperature for June 1-24 was warmer in 10 of the previous 30 years.  However, the heat wave bumped up the mean monthly temperature for June 2021 to 16.6 C.  That's 0.5 degrees warmer than the previous warmest June, when it averaged 16.1 C in 2015.  

So what caused this extraordinary event?  It was the result of an unusually large wave in the jet stream, which may have been caused by a tropical system interacting with the jet stream in the eastern Pacific. This created a strong upper-level high pressure ridge over the BC Interior, which results in sinking air and warm temperatures.

Victoria gets this situation fairly often during the summer, although this was already an unusually strong ridge – one of the strongest ever measured. The heat was then amplified by a low pressure trough approaching the coast at just the right time and location to maximize this event. The pressure differential created a strong southeasterly flow from the Interior out to the coast. The warm air from the Interior was heated even more as it crossed the Coast Mountains and compressed as it descended towards the coast (this is a phenomena like the hot Santa Ana winds in Southern California).

On a typical hot day in Victoria, rising warm air over the land draws in cool air from the Strait of Juan de Fuca, resulting in a cooling sea breeze – especially for areas near the Strait like Esquimalt, James Bay and Fairfield. Victoria Gonzales, being so close to the Strait, is often one of the cooler spots in the region on hot summer days, several degrees cooler than areas further inland. In this case, the strong northerly breeze that resulted from the flow of hot air from the Interior blocked the sea breeze from developing. As a result, Gonzales, with a maximum temperature of 39.8 C on June 28, was the hottest of all the Environment Canada recording sites in the region.

Another factor may have been the time of year when this happened. Many people seemed surprised about how early in the summer this heat wave occurred, given that we usually get our warmest average temperatures in late July or early August. However, if you look at the top 10 hottest days ever recorded in Victoria, 6 of them occurred between June 25 and July 1. It may be that the very long days and strong sun this time of year (close to the summer solstice) contributes to these heat waves.

So the unprecedented heat was the result of all these factors combining in just the right way to create the “perfect” extreme heat situation. This combination of events is unlikely to be repeated any time soon.

Given the extraordinary and historical nature of this heat wave, it is worthwhile looking at some of the other temperatures recorded elsewhere in B.C., Washington, and Oregon.

First, some maximum temperatures for the rest of Vancouver Island, with several locations topping 40 degrees C.  Port Alberni, as is typical, recorded the highest temperature on the Island, with 42.7 C.

Next, several locations in Metro Vancouver, the Fraser Valley, Howe Sound, and Sunshine Coast.  Vancouver Harbour, right near the water and with westerly breezes, was one of the "cooler" spots at 33.8 C.  However, several locations in Metro Vancouver were at or above 40 C.  Temperatures were even hotter - around 43 C - in Abbotsford, Squamish, and Whistler.  

Both Seattle (42.2 C) and Portland (46.7 C) broke all-time maximum records.

Finally, in the B.C. Interior, several locations reached or exceeded the old Canada-wide all-time maximum record of 45.0 set in Middale and Yellow Grass, SK in 1937.  This included Lytton reaching an amazing 49.6 C to set a new Canadian national temperature record, and the record for the highest temperature ever recorded north of 45 degrees N.  

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.  

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

The Sunniest Month in Canadian History

I've already mentioned that Victoria is the sunniest place in B.C. and one of the sunniest cities in Canada.  Well, here's some more proof of just how sunny it is here.  I came across the following list of the sunniest months ever recorded in Canada.  (This is based on Environment Canada measurements from all ten provinces, but doesn't include locations in the territories  since some northern locations get 24 hour daylight in June and July.)  Amazingly, while the statistics came from hundreds of weather sites across Canada, Victoria Gonzales or Victoria Airport accounted for 5 of the 8 sunniest months on record, including the top 4 sunniest months ever recorded in Canada:

	Station	Month	Hours
1	Victoria Airport	July 2013	432.8
2	Victoria Gonzales	July 1985	426.0
3	Victoria Gonzales	July 1958	424.7
4	Victoria Airport	July 1985	421.5
5	Manyberries, AB	July 1985	414.0
6	Cranbrook, BC	July 1985	413.0
7	Medicine Hat, AB	July 1991	413.0
8	Victoria Gonzales	July 1960	410.7

Sunshine measurements stopped at Victoria Gonzales in 1988.  Gonzales typically gets about 6% more sunshine than the Victoria Airport, so if we had still been measuring sunshine at Gonzales in 2013, there is a very good chance that it would have topped the amount at the Victoria Airport, which currently holds the title of sunniest month on record in Canada.  So if you lived in Victoria in July 2013, then you can rightly claim that you experienced the sunniest month ever recorded in Canada, outside the Arctic!  If you've lived in Victoria since 1958, then you have experienced the top 3 sunniest months in Canadian history!

So why is Victoria so sunny in the summer?  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 B.C.'s South Coast with generally sunny, dry weather.  In Victoria, this is enhanced by the Olympic Mountain rain shadow effect.  Victoria's location, surrounded by the cool water of the Strait of Juan de Fuca, also helps since it inhibits the formation of convective clouds (the type that form thunderstorms), resulting in exceptionally clear skies in the summer.