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.