The official National Weather Service forecast for Rockwell City — 42.3953°N, 94.6339°W, 55.6 miles from I-35.
| Calhoun County | J | F | M | A | M | J | J | A | S | O | N | D | Year |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg high °F | 28 | 32 | 46 | 60 | 71 | 81 | 84 | 81 | 76 | 63 | 47 | 33 | 58 |
| Avg low °F | 10 | 14 | 26 | 37 | 48 | 59 | 63 | 60 | 52 | 40 | 27 | 16 | 38 |
| Precip in | 0.9 | 1.0 | 1.9 | 3.3 | 4.6 | 4.9 | 3.8 | 4.0 | 2.7 | 2.4 | 1.4 | 1.2 | 32.1 |
1996–2025 normals for Calhoun County — the climate division Rockwell City sits in. All-time county record high 104.7°F (1955-07-31); record low -27.7°F (1970-01-21). Source: NOAA / National Weather Service.