Friday, March 1, 2024

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.

Monday, January 8, 2024

Victoria's weather in 2023: Warmer and much drier than normal

 

2023 was warmer than normal in Victoria, and also much drier than normal - it was the 5th driest year on record at Victoria Gonzales (1898-2023).

The mean temperature for 2023 (11.0 C) was warmer than the 30-year average of 10.7 C.  2023 was tied for the 14th warmest year (out of 125 years) at Victoria Gonzales, so it almost made it into the top 10 percentile.   

The table below compares mean monthly temperatures in 2023 with the 30-year averages.  August was the warmest on record, while December was tied for the warmest.  May was also unusually warm.  January, July, and October were all about half a degree warmer than normal.  This was offset by February and April, which were both more than one degree colder than normal.  March and September were also slightly colder than normal.  


The hottest temperature of 2023 was 32.5 degrees on August 14.  There were 3 days in 2023 with daily maximums above 30 C, compared with the normal of 1.1 days.  There were 13 days with daily maximums above 25 degrees, compared with the average of 9.1 days.    

The coldest temperature of 2022 was -4.9 C on February 24.  There were 7 days in 2023 when the temperature went below 0, a little less than the long-term average of 9.5 days.  Of these days, 2 were in January and 5 were in February.  There were no below freezing temperatures in November or December.

The chart below shows the daily maximum and minimum temperatures at Victoria Gonzales in 2023, compared with the long-term normal temperatures.  The chart shows the colder than normal temperatures in February and April, as well as the warmer than normal temperatures in May, August, and December.



Victoria's annual precipitation of 431 mm in 2023 was just two-thirds of the average of 656 mm, making it the 5th driest year on record.  The table below compares the monthly precipitation in 2023 with the 30-year average.  Every  month had below normal rainfall.  January was especially dry, accounting for more than one third of the annual precipitation shortfall.




The chart below shows daily and cumulative precipitation at Victoria Gonzales for 2023.  The very dry January meant that cumulative precipitation fell below normal right from the beginning of the year, and continued to fall further below normal as the year progressed.  Along with January, late December was also unusually dry, with just 16 mm of rain during the last 3 weeks of December - it's normally one of the wettest times of the year in Victoria.






There were 118 days with measurable precipitation in 2023, compared with the normal 132 days.  The wettest day was November 2nd, with 34.8 mm of rain.  There were 2 days with more than 25 mm of rain in 2023, slightly below the average of 2.9 days annually.  

The chart below compares annual precipitation at Victoria Gonzales in 2023 with other locations in North America.  Victoria had less rainfall than Los Angeles, which was unusually wet in 2023.  Vancouver's annual precipitation in 2023 (1,159 mm) was 2.7 times as much as Victoria's.




Victoria received only 4 cm of snow in 2023, all of if in February.  That's only about 20-25% of normal.  That followed a very snowy year in 2022.  


Friday, December 1, 2023

Fall 2023: fairly normal overall

 Meteorological fall is from September 1 to November 30.  Fall 2023 was fairly close to normal temperature and rainfall.

Overall, the mean fall temperature at Victoria Gonzales was 11.3 degrees, which is just 0.1 degrees warmer than the 30-year average.  September was 0.3 degrees C cooler than average, while October was 0.3 degrees C warmer than average.  November was very close to average (just 0.1 degrees warmer).

The chart below shows the daily maximum and minimum temperatures at Victoria Gonzales during fall 2023, compared with the 30-year averages.  Temperatures generally stayed close to the average, with some variability, as is typical.  The most significant departures from normal temperatures were a warm spell in early October, when highs reached 23.4 C, and a cold snap in late October, when overnight lows dipped to 2.2 C.  

Daily Max & Min temperatures in Victoria, Fall 2023



Overall, the warmest temperature of the fall was 26.4 C on September 2nd.  The coldest temperature was 2.2 C on October 28th and again on November 24 & 25.

Victoria typically experiences 9.7 days each fall when the maximum temperature exceeds 20 C.  In 2023, there were only 7 such days (5 in September and 2 in October).  That's a big contrast from fall 2022 when there were 25 days when the temperature exceeded 25 C.  

On the other hand, Victoria typically only experiences 0.9 days each fall when the overnight low temperature falls below freezing.  In 2023, there were no such days, with the temperature not dropping any lower than 2.2 C.  

Victoria received 162 mm of rain from September to November, 29% less than the 30-year average fall rainfall of 227 mm.   

Victoria had 36 days with measurable rainfall this fall, close to the normal 37.8 days.  The number of days with measurable rainfall was close to normal for each month.  There were 7 days with measurable rain in September (normal 7.8), 12 days in October (normal 12.8) and 17 days in November (normal 17.4).  

The chart below shows daily precipitation during fall 2023, and compares the cumulative precipitation with the 30-year average.   The first half of September was dry, then rainfall was close to normal from mid-September to mid-November.  The last week of November was also dry, with 7 consecutive rainless days.  The wettest day of the fall was November 2nd, with 34.8 mm of rain.  

Daily & cumulative rainfall in Victoria, fall 2023

The chart below compares Fall 2023 rainfall in various locations around the region.  As is typically the case, Victoria was drier than other nearby locations, thanks to the Olympic Mountain Rainshadow.  Victoria's 162 mm of rain was 71% of normal.  The Victoria Airport received 233 mm of rain - 44% more than Victoria Gonzales.  Vancouver received 329 mm of rain - only about 69% of its normal fall rain, but still more than double Victoria's rainfall.  Seattle received 308 mm of rain, which was slightly wetter than normal.  

Fall 2023 rainfall

The chart below shows the number of sunny, partly cloudy, and mostly cloudy days during fall 2023.  Overall, fall 2023 was sunnier than normal.  There were 34 mostly sunny days (normal 28.3), 37 partly cloudy days (normal 32.1), and 20 mostly cloudy days (normal 30.5).  September and October were close to normal, but November was much sunnier than normal, with twice the usual number of sunny days and just over half the normal mostly cloudy days. 






Saturday, September 30, 2023

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 202
3, 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 2022 slightly less sunny than normal.  June and July were both cloudier than normal, while August was sunnier than 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.





Wednesday, August 2, 2023

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.

Saturday, June 3, 2023

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.




Wednesday, May 31, 2023

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.