The official National Weather Service forecast for Decorah — 43.3033°N, 91.7857°W, population 7,993, 62.6 miles from I-380.
| Winneshiek County | J | F | M | A | M | J | J | A | S | O | N | D | Year |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg high °F | 25 | 29 | 43 | 57 | 69 | 79 | 82 | 80 | 74 | 60 | 44 | 30 | 56 |
| Avg low °F | 8 | 11 | 24 | 35 | 46 | 57 | 61 | 58 | 51 | 38 | 27 | 15 | 36 |
| Precip in | 1.1 | 1.2 | 2.0 | 3.7 | 4.9 | 6.1 | 4.6 | 4.3 | 3.5 | 2.8 | 1.8 | 1.5 | 37.5 |
1996–2025 normals for Winneshiek County — the climate division Decorah sits in. All-time county record high 101.0°F (1988-08-01); record low -35.8°F (1951-01-30). Source: NOAA / National Weather Service.