The official National Weather Service forecast for Fort Calhoun — 41.4558°N, 96.0264°W, 7.1 miles from I-29.
| Washington County | J | F | M | A | M | J | J | A | S | O | N | D | Year |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg high °F | 32 | 36 | 50 | 63 | 73 | 83 | 86 | 84 | 78 | 65 | 50 | 36 | 61 |
| Avg low °F | 14 | 17 | 28 | 39 | 50 | 62 | 66 | 63 | 55 | 42 | 29 | 18 | 40 |
| Precip in | 0.8 | 0.9 | 1.8 | 3.1 | 4.9 | 4.6 | 3.4 | 4.0 | 3.0 | 2.4 | 1.3 | 1.2 | 31.4 |
1996–2025 normals for Washington County — the climate division Fort Calhoun sits in. All-time county record high 105.8°F (1995-07-13); record low -24.7°F (1974-01-12). Source: NOAA / National Weather Service.