The official National Weather Service forecast for Fairfield — 41.0086°N, 91.9627°W, population 9,211, 47.4 miles from I-80.
| Jefferson County | J | F | M | A | M | J | J | A | S | O | N | D | Year |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg high °F | 31 | 36 | 50 | 62 | 72 | 82 | 85 | 83 | 78 | 65 | 50 | 37 | 61 |
| Avg low °F | 14 | 17 | 29 | 39 | 51 | 61 | 64 | 62 | 54 | 42 | 30 | 20 | 40 |
| Precip in | 1.5 | 1.6 | 2.4 | 3.6 | 5.1 | 5.1 | 3.9 | 3.8 | 3.3 | 3.1 | 1.9 | 1.8 | 37.1 |
1996–2025 normals for Jefferson County — the climate division Fairfield sits in. All-time county record high 106.2°F (2012-07-24); record low -25.6°F (2019-01-31). Source: NOAA / National Weather Service.