The reconstruction of Vernon’s climate record from 1951 to today, comes from one weather station with three seperate records (see map Figure 1): 

1) Cold Stream Ranch, station ID 128580. January 1, 1951 to March 31, 1997.

2) Cold Stream Ranch, station ID 128581. June 1, 1991 to March 17, 2008.

3) Cold Stream Ranch, station ID 128582. January 1, 2005 to today.

        In this analysis, the weather station south of the Summerland Ornamental Gardens was set as the primary station for Summerland. Data from Penticton was used to complete the climate record and was adjusted for micro-climatic differences using a statistical technique.

Annual Changes

        Displayed in Figure 2 is Vernon’s annual average mean temperature from 1951 to 2025. Annual average mean temperature is calculated by adding up all of the daily mean temperatures and dividing that value by the number of days in the year (either 365 or 366). Daily mean temperature is calculated by adding the daily maximum temperature and the daily minumum temperature and dividing that value by 2. According to the best-fit line, annual average mean temperature has increased by 2.35°C over the the 75-year record.

        

        Figure 3 shows annual average maximum and minimum temperature from 1951 to 2025.  Both temperature measures show a stead increase over the period. Annual average maximum temperatures and annual average minimum temperatures are changing at the same rate of increase.

       

        Figure 4 shows annual precipitation from 1951 to 2025.  Annual precipitation is the total amount of rain and snow that fell during the calendar year. A number of years were not plotted on the graph because they had a significant number of missing observations. The average annual precipitation for the remaing years was 426 mm.

Seasonal Changes

        Figure 5 shows spring (March, April, and May) average mean temperatures from 1951 to 2025. Over this 75-year period, spring temperatures have increase by 2.36°C.

        Figure 6 shows summer (June, July, and August) average mean temperatures from 1951 to 2025. Over this 75-year period, summer temperatures have increase by 3.02°C.

        Figure 7 shows fall (September, October, and November) average mean temperatures from 1951 to 2025. Over this 75-year period, fall temperatures have increase by 1.99°C.

        Figure 8 shows winter (previous year December, January, and February) average mean temperatures from 1951 to 2025. Over this 75-year period, winter temperatures have increase by 1.99°C.

Monthly Changes

        Figure 9 shows the historical change in average monthly minimum temperatures for three periods: 1951 to 1980, 1981 to 2010, and 2011 to 2025. Between 1951 to 1980 and 2011 to 2025, average monthly minimum temperatures rose between 1.15 to 3.84°C in 11 months. The greatest rise in temperature occurred in the January, March, May, July, and August.  February saw average monthly maximum temperature declined by 0.01°C between 1951 to 1980 and 2011 to 2025.

        Figure 10 displays the historical change in average monthly maximum temperatures for three periods: 1951 to 1980, 1981 to 2010, and 2011 to 2025. Between 1951 to 1980 and 2011 to 2025, average monthly maximum temperatures rose between 0.07 to 3.10°C.  The greatest rise in temperature occurred in the January, March, May, July, August, and September. 

Days Greater Than 30°C

        In Canada, an extreme maximum daily temperature is defined as an event where the temperature is greater than (>) 30°C. Figure 11 shows the yearly number of extreme maximum daily temperature events that occurred in Vernon from 1951 to 2025. These high temperature events average around 12 at the beginning of temperature record to around 34 by 2025, a 180% increase.

Days Less Than 0°C

        Figure 12 shows the number of daily minimum temperature events less than (<) 0°C per year from 1951 to 2025. Over this 75-year period, the annual number of these events has dropped by 25.

Figure 2 Vernon’s annual average mean temperatures from 1951 to 2025. Annual average mean temperature has been steadily increasing at a rate of 0.31°C per decade according to linear regression analysis.

Figure 3 Vernon’s annual average maximum and minimum temperatures from 1951 to 2025. Annual average maximum temperature has been steadily increasing at a rate of 0.31°C per decade, while annual average minimum temperature has been steadily increasing at a rate of 0.32°C per decade according to linear regression analysis.

Figure 6 Vernon’s summer average mean temperatures from 1951 to 2025. Summer average mean temperature has been steadily increasing at a rate of 0.40°C per decade according to linear regression analysis.

Figure 7 Vernon’s fall average mean temperatures from 1951 to 2025. Fall average mean temperature has been steadily increasing at a rate of 0.26°C per decade according to linear regression analysis.

Figure 8 Vernon’s winter average mean temperatures from 1951 to 2025. Winter average mean temperature has been steadily increasing at a rate of 0.25°C per decade according to linear regression analysis.

Figure 9 The historical change in average monthly minimum temperatures for three periods: 1951 to 1980, 1981 to 2010, and 2011 to 2025.

Figure 10 The historical change in average monthly maximum temperatures for three periods: 1951 to 1980, 1981 to 2010, and 2011 to 2025.

Figure 12 Yearly number of minumum daily temperature events < 0°C from 1951 to 2025 in Vernon. Minimum daily temperature events < 0°C have been steadily decreasing at a rate of 3.3 days per decade according to linear regression analysis.

Figure 1 Location of the weather station used to reconstruct Vernon’s climate record.