The official National Weather Service forecast for Oskaloosa — 41.2964°N, 92.6444°W, population 12,541, 28.3 miles from I-80.
| Mahaska 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 | 36 | 61 |
| Avg low °F | 14 | 17 | 29 | 39 | 50 | 61 | 64 | 62 | 54 | 42 | 30 | 19 | 40 |
| Precip in | 1.2 | 1.4 | 2.1 | 3.5 | 4.8 | 5.1 | 4.1 | 4.0 | 3.1 | 3.0 | 1.9 | 1.5 | 35.7 |
1996–2025 normals for Mahaska County — the climate division Oskaloosa sits in. All-time county record high 105.2°F (2012-07-24); record low -27.5°F (1996-02-03). Source: NOAA / National Weather Service.