Location and Geography

            Sun Peaks Resort is found in the interior of British Columbia, approximately 55 kilometers northeast of the city of Kamloops, at latitude 50.887281° North and longitude 119.891113° West. Sun Peaks Resort has a base elevation of 1255 meters above sea level and consists of three mountains: Tod Mountain, Mount Morrissey, and Sundance Mountain. Tod Mountain is the tallest peak of the three at 2152 meters and has ski runs facing mainly South to Southeast. The next tallest peak is Sundance Mountain at 1675 meters. Ski runs on Sundance Mountain face mainly South to Southwest. The final peak, Mount Morrissey, has a maximum elevation of 1730 meters and its runs are oriented in a Northeast direction.

            Sun Peaks Ski Resort has base and peak elevations, as well as vertical relief, that is comparable to most of the other ski resorts found in interior British Columbia (Figure 1). Sun Peaks Resort is the second largest ski area in Canada, with 1728 hectares of available terrain with 126 marked trails. This ski area is accessed by 11 lifts found on the resort’s three mountains.

            The climate of Sun Peaks Ski Resort in winter is quite cold because of its distance from the moderating influence of the Pacific Ocean. During the winter months, the resort is frequently under the influence of Continental Polar and Continental Arctic air masses. Winter precipitation is the result of a combination of mid-latitude cyclones and orographic lifting. Table 1 provides monthly statistics for temperature and precipitation for the months of November to April at the ski resort’s mid-elevation.

Climate Indicator Variables

            Four indicator variables were generated from ClimateBC to evaluate whether human induced climate change is having an impact on Sun Peaks Ski Resort at its mid-elevation 1639 m.  

• Winter Mean Temperature - the average of the daily temperature means for the winter months of December, January and February.
  
  
• Winter Degree Days < 0°C - the cumulative sum of days with mean temperatures below (less than) zero taken from the winter months of December, January and February. This calculation uses the absolute values of daily mean temperatures < (below) 0°C. For example, four days with temperatures +5°C, -2°C, -11°C and -6°C would produce a degree day < 0°C value of 19°C (2+11+6).
  
  
• Winter Snowfall – accumulated snowfall for the winter months of December, January and February. This variable is calculated as the equivalent depth of liquid water in millimeters that will remain after a known volume of snow is entirely melted. This estimate is usually made at meteorological stations using known quantities for the water density of snow and measured depth of the snow. Alternatively, some meteorological stations employ the use of a Nipher snow gauge that melts any captured snow, converting it into a water measurement in millimeters.
  
  
• Winter Rainfall – accumulated rainfall for the winter months of December, January and February. This variable is calculated in millimeters.

ClimateBC Software – Historic Data

            This website uses a high-quality, spatially interpolated climate database program, ClimateBC version 7.70, to compute directly calculated and derived climate variables for the various British Columbian ski resorts based on latitude, longitude, and elevation (Wang et al., 2016 and Wang et al., 2025). Climate databases of this type are very useful for studies in which climate scientists seek to determine the impact of climate change on a particular human socio-economic system. ClimateBC uses numerical downscaling to produce output at the local-scale and has historic datasets for the period 1901 to 2025. 

ClimateBC Software – Future Climate Model Forecasts

            ClimateBC also includes future simulated climate forecasts for the 21st century (Mahoney et al., 2022). These forecasts are generated by various Coupled Model Intercomparison Project Phase 6 (CMIP6) global climate models (GCMs) used in the Intergovernmental Panel on Climate Change (IPCC) 6th Assessment Reports on climate change. However, ClimateBC contains the output of a subset of 13 of the over 44 global climate models used in the most recent IPCC assessment report. The researchers who developed ClimateBC carefully selected this group to ensure that the forecasts made by these 13 models best replicate the range of results produced by the models used in the latest IPCC reports (Mahoney et al., 2022). The output on this webpage used an ensemble of eight models with an equilibrium climate sensitivity of 3.4°C to create a single averaged forecast. The 13 global climate models available in ClimateBC are shown in Table 2. 

Winter Mean Temperature

            Winter mean temperatures have steadily increased from 1901 to 2025, with a rate of 0.19°C per decade based on linear regression analysis, as shown in Figure 2. The best-fit regression line predicts an average winter mean temperature of approximately -6.4°C in 2025. Particularly, the graph reveals that many of the warmest winters at Sun Peaks Ski Resort over the last 45 years have been associated with El Niño events.

            Figure 3 indicates that winter mean temperatures will continue to increase in the 21st century, reaching -4.9 and -3.1°C, respectively, under the SSP2-4.5 and SSP5-8.5 emission scenarios by 2090. 

Winter Degree Days < 0°C

                Winter degree days <0°C have steadily decrease from 1901 to 2025, at a rate of 15.5°C per decade, as shown in Figure 4 based on linear regression analysis. The best-fit regression line predicts an average winter degree days of approximately 629°C in 2025. 

            Figure 5 displays that winter degree days <0°C will continue to decrease in the 21st century, falling to 510 and 377°C, respectively, under the SSP2-4.5 and SSP5-8.5 emission scenarios by 2090. 

Winter Snowfall

                Winter snowfall has declined from 1901 to 2025, at a rate of 0.3 mm water equivalent per decade, as shown in Figure 6 based on linear regression analysis. This estimate is not statistically significant. The best-fit regression line predicts an average winter snowfall of about 246 mm water equivalent in 2025. 

            Figure 7 displays that winter snowfall (mm water equivalent) will continue to decrease in the 21st century, dropping to 267 and 214 mm, respectively, under the SSP2-4.5 and SSP5-8.5 emission scenarios by 2090. 

Winter Rainfall

            Winter rainfall has increased from 1901 to 2025, at a rate of 2.5 mm per decade, as described in Figure 8 based on linear regression analysis. The best-fit regression line predicts an average winter rainfall of about 53 mm water equivalent in 2025. 

            Figure 9 indicates that winter rainfall (mm) will continue to increase in the 21st century, reaching to 86 and 155 mm, respectively, under the SSP2-4.5 and SSP5-8.5 emission scenarios by 2090. 

References

Knutti, R., D. Masson, and A. Gettelman. 2013. Climate model genealogy: Generation CMIP5 and how we got there. Geophysical Research Letters 40, 1194–1199. DOI:10.1002/grl.50256

Mahony, C.R., T. Wang, A. Hamann, and A.J. Cannon. 2022. A CMIP6 ensemble for downscaled monthly climate normals over North America. International Journal of Climatology 42 (11), 5871-5891. DOI:10.1002/joc.7566

Wang, T., A. Hamann, and Z. Sang. 2025. Monthly high‐resolution historical climate data for North America since 1901. International Journal of Climatology 45 (3), e8726. DOI: 10.1002/joc.8726

Wang, T., A. Hamann, D. Spittlehouse, and C. Carroll. 2016. Locally downscaled and spatially customizable climate data for historical and future periods for North America. PLoS ONE 11(6): e0156720. DOI:10.1371/journal.pone.0156720

Figure 1  Base, middle, and peak elevations of the British Columbian ski resorts discussed on this website. The ski resorts are ordered along the X-axis based on their longitude. The resorts are labeled as follows: A = Mount Washington, B = Cypress Mountain, C = Whistler Blackcomb, D = Sasquatch Mountain, E = Sun Peaks, F = Silver Star, G = Big White, H = Revelstoke Mountain, I = Red Mountain, J = Whitewater Mountain, K = Panorama, L = Sunshine Banff, and M = Fernie. The grey dotted line represents the average height of the ski resorts, measured by linear regression from west to east. Note that the base elevation for Whistler Blackcomb and Revelstoke Mountain is considered to be at the top of their Gondola lifts, which are located at  roughly 1080 meters and 790 meters, respectively, rather than the village elevation.

Table 1  Average monthly values of selected climate variables for Sun Peaks Ski Resort at an elevation of 1639 meters. Data is derived for the period of 1991 to 2020 as determined by ClimateBC (version 7.70). 

Table 2  Global climate models available in ClimateBC (version 7.70). * Identifies the climate models available in the eight member ensemble used for the future forecasts shown on this website.

Figure 2  Yearly observations of winter mean temperatures (°C) from 1901 to 2025 at Sun Peaks Ski Resort (elevation 1639 m) as derived from the climate database ClimateBC. The orange line is the best-fit linear regression line and the green dash lines show the 5% and 95% prediction thresholds.   

Figure 3  Predicted winter mean temperatures (°C) for the period 2030 to 2090 at Sun Peaks Ski Resort (elevation 1639 m). These predictions are based on an eight climate model ensemble using the SSP2-4.5 and SSP5-8.5 emission scenarios, as derived from the climate database ClimateBC. Additionally, the figure includes the observed winter mean temperatures from 1901 to 2025. The orange line is the best-fit linear regression line and the green dash lines show the 5% and 95% prediction thresholds.   

Figure 4  Yearly observations of winter degree days <0°C from 1901 to 2025 at Sun Peaks Ski Resort (elevation 1639 m) as derived from the climate database ClimateBC. The orange line is the best-fit linear regression line and the green dash lines show the 5% and 95% prediction thresholds.   

Figure 5  Predicted winter degree days <0°C for the period 2030 to 2090 at Sun Peaks Ski Resort (elevation 1639 m). These predictions are based on an eight climate model ensemble using the SSP2-4.5 and SSP5-8.5 emission scenarios, as determined from the climate database ClimateBC. Additionally, the figure includes the observed winter degree days <0°C from 1901 to 2025. The orange line is the best-fit linear regression line and the green dash lines show the 5% and 95% prediction thresholds.   

Figure 6  Yearly observations of winter snowfall (mm water equivalent) from 1901 to 2025 at Sun Peaks Ski Resort (elevation 1639 m) as derived from the climate database ClimateBC. The orange line is the best-fit linear regression line and the green dash lines show the 5% and 95% prediction thresholds.   

Figure 7  Predicted winter snowfall (mm water equivalent) for the period 2030 to 2090 at Sun Peaks Ski Resort (elevation 1639 m). These predictions are based on an eight climate model ensemble using the SSP2-4.5 and SSP5-8.5 emission scenarios, as determined from the climate database ClimateBC. Additionally, the figure includes the observed winter snowfall from 1901 to 2025. The orange line is the best-fit linear regression line and the green dash lines show the 5% and 95% prediction thresholds.   

Figure 8  Yearly observations of winter rainfall (mm) from 1901 to 2025 at Sun Peaks Ski Resort (elevation 1639 m) as derived from the climate database ClimateBC. The orange line is the best-fit linear regression line and the green dash lines show the 5% and 95% prediction thresholds.   

Figure 9  Predicted winter rainfall (mm) for the period 2030 to 2090 at Sun Peaks Ski Resort (elevation 1639 m). These predictions are based on an eight climate model ensemble using the SSP2-4.5 and SSP5-8.5 emission scenarios, as determined from the climate database ClimateBC. Additionally, the figure includes the observed winter rainfall from 1901 to 2025. The orange line is the best-fit linear regression line and the green dash lines show the 5% and 95% prediction thresholds.