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Weather & Climate
Jefferson County, Washington, United States
Overview
Climate data and monthly weather averages for Jefferson County.
Key Metrics
Annual Avg
7.2°C
Summer Avg
13.5°C
Winter Avg
1.7°C
Record High
34.4°C
Record Low
-17.4°C
Annual Precipitation
1876.2 mm
Avg Humidity
86%
Summer Humidity
80%
Winter Humidity
92%
Monthly Averages
| Month | High (°C) | Avg (°C) | Low (°C) | Rain (mm) | Humidity (%) | Sunshine (h) | Wind (kph) |
|---|---|---|---|---|---|---|---|
| Jan | 11.8° | 2° | -17.4° | 286.1 | 93% | 32 | 31.6 |
| Feb | 12.9° | 1.6° | -14.1° | 160.7 | 91% | 54 | 34.3 |
| Mar | 19.3° | 2.8° | -9.5° | 224.4 | 90% | 88 | 34.6 |
| Apr | 23.4° | 5.1° | -5° | 137.1 | 85% | 125 | 27.1 |
| May | 25.9° | 9° | -0.9° | 85.9 | 81% | 163 | 27.3 |
| Jun | 31.1° | 11.4° | 2.3° | 62.7 | 81% | 172 | 22.3 |
| Jul | 34.4° | 14.4° | 4.3° | 31.3 | 79% | 196 | 18.7 |
| Aug | 33.9° | 14.6° | 4.6° | 42.5 | 79% | 168 | 29.2 |
| Sep | 32° | 12° | 0.8° | 85.5 | 82% | 117 | 28.3 |
| Oct | 23.6° | 7.7° | -3.5° | 198.1 | 88% | 71 | 30.3 |
| Nov | 14.9° | 3.8° | -13° | 291.9 | 92% | 37 | 40.6 |
| Dec | 11.3° | 1.4° | -14.6° | 270 | 93% | 26 | 38.4 |
Frequently Asked Questions
Sources: NASA POWER · Last updated: 2025
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