The official National Weather Service forecast for Washington — 41.2992°N, 91.6929°W, population 6,846, 27.7 miles from I-80.
| Washington County | J | F | M | A | M | J | J | A | S | O | N | D | Year |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg high °F | 31 | 36 | 49 | 62 | 72 | 82 | 85 | 83 | 78 | 64 | 50 | 36 | 61 |
| Avg low °F | 14 | 17 | 28 | 38 | 50 | 60 | 64 | 61 | 54 | 41 | 30 | 19 | 40 |
| Precip in | 1.3 | 1.6 | 2.4 | 3.6 | 5.1 | 5.1 | 3.9 | 3.9 | 3.2 | 3.2 | 1.8 | 1.7 | 36.8 |
1996–2025 normals for Washington County — the climate division Washington sits in. All-time county record high 105.4°F (2012-07-24); record low -28.2°F (2019-01-31). Source: NOAA / National Weather Service.