| Average climate data for Crater Lake, United States | |||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Month | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Year |
| Average maximum temperature (°C) | 1 | 2 | 3 | 5 | 10 | 14 | 20 | 21 | 17 | 11 | 3 | 1 | 21 |
| Average minimum temperature (°C) | -8 | -8 | -7 | -5 | -2 | 1 | 5 | 5 | 2 | -1 | -6 | -8 | -8 |
| Average precipitation (mm) | 238 | 194 | 188 | 139 | 90 | 58 | 26 | 26 | 51 | 111 | 258 | 296 | 1,674 |
| Average rainfall days (days) | 18 | 16 | 18 | 16 | 11 | 8 | 4 | 4 | 6 | 10 | 17 | 18 | 146 |
| Average snowfall (mm) | 2,229 | 1,822 | 1,868 | 1,175 | 409 | 105 | 3 | 0 | 84 | 460 | 1,792 | 2,336 | 12,282 |
| Average snowfall days (days) | 16 | 14 | 16 | 12 | 6 | 2 | 0 | 0 | 1 | 5 | 13 | 16 | 102 |
| Average daily daylight hours (h) | 9 | 10 | 12 | 13 | 14 | 15 | 15 | 13 | 12 | 11 | 9 | 9 | 12 |
| Average daily sunshine hours (h) | 4 | 5 | 7 | 8 | 10 | 11 | 12 | 11 | 9 | 7 | 3 | 3 | 7 |
| Average UV index | 2 | 2 | 4 | 6 | 8 | 9 | 9 | 8 | 6 | 4 | 2 | 1 | 5 |
The warmest month, with the highest average maximum temperature, is August (20.9 °C). The month with the lowest average maximum temperature is December (1 °C). Overall, the average maximum temperature over the whole year is 9.1 °C.
The month with the highest average minimum temperature is July (4.8 °C). The coldest month, with the lowest average minimum temperature, is February (-7.8 °C). Overall, the average minimum temperature over the whole year is -2.6 °C.
The wettest month, with the highest amount of precipitation, is December (295.5 mm). The driest month, with the least amount of precipitation, is August (25.7 mm). Over the whole year there are 1,673.6 mm of rainfall on average.
The month with the most days of rain is December (18.2 days). The month with the fewest days of rain is August (4 days). Over the whole year there are 146 days of rain on average.
The month with the most snowfall is December (2,336 mm). The month with the least snowfall is August (0 mm). Over the whole year there are 12,282.3 mm of snowfall on average.
The month with the most days of snowfall is December (16.4 days). The month with the fewest days of snowfall is August (0 days). Over the whole year there are 101.6 days of snowfall on average.
The month with the longest days, so the most daylight, is June (Average daylight: 15 h). The month with the shortest days, so the least daylight, is December (Average daylight: 9 h). Over the whole year there are 11.9 h of daylight per day on average.
The month with the most sunshine per day is July (Average sunshine: 12 h). The month with the least sunshine per day is December (Average sunshine: 3 h). Over the whole year there are 7.5 h of sunlight per day on average.
The months with the highest average UV index are June and July (UV index: 9). The month with the lowest average UV index is December (UV index: 1). Over the whole year the average UV index is 5.1.
