The official National Weather Service forecast for Ottumwa — 41.02°N, 92.4113°W, population 25,019, 47 miles from I-80.
| Wapello County | J | F | M | A | M | J | J | A | S | O | N | D | Year |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg high °F | 32 | 37 | 50 | 63 | 72 | 82 | 85 | 84 | 78 | 65 | 50 | 37 | 61 |
| Avg low °F | 15 | 18 | 29 | 40 | 51 | 61 | 65 | 62 | 54 | 42 | 31 | 20 | 41 |
| Precip in | 1.4 | 1.5 | 2.3 | 3.6 | 4.9 | 5.0 | 3.9 | 4.0 | 3.1 | 3.0 | 1.8 | 1.6 | 36.1 |
1996–2025 normals for Wapello County — the climate division Ottumwa sits in. All-time county record high 105.9°F (2012-07-24); record low -25.0°F (1996-02-04). Source: NOAA / National Weather Service.