Average annual temperature is 11.1 °C
Absolute maximum temperature: 39.5 °C
Absolute minimum temperature: -14.2 °C
Number of sunny days: 228 days
Number of rainy days: 113 days
Number of snow days: 24 days
Look at detailed online map of Grand Coulee
* Weather data for Grand Coulee United States is based on climate observations for 2026 year
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Absolute maximum temperature (°C) | 7.3 | 10.1 | 13.6 | 27.9 | 32.1 | 33.2 | 35.9 | 39.5 | 30.9 | 25.7 | 11.1 | 8.7 |
| Average daytime temperature (°C) | 2.0 | 4.5 | 8.0 | 13.2 | 25.2 | 27.2 | 32.0 | 31.5 | 24.0 | 16.6 | 6.5 | 4.1 |
| Average temperature (°C) | -1.2 | -0.6 | 2.4 | 7.9 | 18.9 | 21.2 | 25.6 | 24.9 | 17.9 | 11.1 | 2.9 | 1.4 |
| Average night temperature (°C) | -3.8 | -4.0 | -2.4 | 3.2 | 13.0 | 15.5 | 18.8 | 18.5 | 12.7 | 6.4 | 0.3 | -0.6 |
| Absolute minimum temperature (°C) | -14.2 | -13.3 | -10.1 | -2.0 | 7.7 | 9.0 | 13.6 | 13.2 | 5.0 | -3.6 | -3.9 | -4.3 |
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Daylight maximum duration (h) | 9.0 | 10.0 | 12.0 | 14.0 | 15.0 | 16.0 | 15.0 | 14.0 | 13.0 | 11.0 | 9.0 | 8.0 |
| Daylight mean duration (h) | 8.9 | 10.2 | 11.9 | 13.7 | 15.2 | 16.0 | 15.6 | 14.3 | 12.6 | 10.8 | 9.3 | 8.5 |
| Daylight minimum duration (h) | 8.0 | 9.0 | 11.0 | 12.0 | 14.0 | 15.0 | 15.0 | 13.0 | 11.0 | 10.0 | 8.0 | 8.0 |
| Sunshine mean duration (h) | 3.8 | 6.3 | 8.5 | 9.3 | 12.6 | 13.3 | 13.8 | 11.6 | 10.1 | 8.0 | 5.1 | 3.0 |
| Precipitation (mm) | 39 | 21 | 24 | 59 | 22 | 17 | 3 | 25 | 16 | 22 | 39 | 62 |
| Sunny days | 14 | 20 | 17 | 11 | 15 | 22 | 28 | 25 | 23 | 21 | 19 | 13 |
| Rainy days | 12 | 3 | 7 | 18 | 16 | 8 | 3 | 6 | 7 | 9 | 11 | 13 |
| Snow days | 5 | 5 | 7 | 1 | 0 | 0 | 0 | 0 | 0 | 1 | 0 | 5 |
The best time to visit Grand Coulee during the most sunny months:
Months with the longest average daylight duration in Grand Coulee:
The largest precipitation sum in Grand Coulee is at