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Weather & Climate
Grand Coulee, Washington, United States
Overview
Climate data and monthly weather averages for Grand Coulee.
Key Metrics
Annual Avg
8°C
Summer Avg
20.1°C
Winter Avg
-3.6°C
Record High
38.9°C
Record Low
-30.9°C
Annual Precipitation
411.1 mm
Avg Humidity
68%
Summer Humidity
48%
Winter Humidity
90%
Monthly Averages
| Month | High (°C) | Avg (°C) | Low (°C) | Rain (mm) | Humidity (%) | Sunshine (h) | Wind (kph) |
|---|---|---|---|---|---|---|---|
| Jan | 6.8° | -4.4° | -30.9° | 51.5 | 94% | 35 | 38 |
| Feb | 12.3° | -2.2° | -21° | 32.8 | 84% | 63 | 41.4 |
| Mar | 20.2° | 2.5° | -22° | 45.6 | 75% | 110 | 42.2 |
| Apr | 26.8° | 7.1° | -5.8° | 30.6 | 64% | 157 | 43.1 |
| May | 32.7° | 13.1° | -2.7° | 37.2 | 58% | 198 | 43.2 |
| Jun | 37.1° | 17.1° | 1.6° | 29.1 | 54% | 209 | 31.4 |
| Jul | 38.9° | 22.1° | 6° | 10.2 | 45% | 234 | 37.7 |
| Aug | 37.6° | 21.2° | 6.2° | 9.9 | 45% | 195 | 38.7 |
| Sep | 34.2° | 15.5° | -0.9° | 15.6 | 52% | 138 | 37.5 |
| Oct | 27.9° | 7.7° | -10.2° | 37.5 | 67% | 89 | 41.5 |
| Nov | 16.9° | 0.7° | -20.7° | 50.7 | 83% | 44 | 50.8 |
| Dec | 8.3° | -4.2° | -25.5° | 60.4 | 91% | 28 | 42.4 |
Frequently Asked Questions
Sources: NASA POWER · Last updated: 2025
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