The official National Weather Service forecast for Dewey — 36.7959°N, 95.9355°W, 39.2 miles from I-44. Forecasts here are written by NWS TSA, this county’s forecast office.
| Washington County | J | F | M | A | M | J | J | A | S | O | N | D | Year |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg high °F | 47 | 52 | 62 | 71 | 78 | 87 | 92 | 92 | 85 | 73 | 61 | 50 | 71 |
| Avg low °F | 25 | 28 | 38 | 47 | 57 | 67 | 71 | 69 | 61 | 48 | 37 | 28 | 48 |
| Precip in | 1.6 | 1.7 | 3.2 | 4.2 | 6.2 | 5.2 | 3.4 | 3.5 | 3.4 | 3.7 | 2.4 | 1.8 | 40.3 |
1996–2025 normals for Washington County — the climate division Dewey sits in. All-time county record high 113.1°F (1954-07-14); record low -14.1°F (2021-02-17). Source: NOAA / National Weather Service.