The official National Weather Service forecast for Reinbeck — 42.3236°N, 92.5994°W, 17.2 miles from I-380.
| Grundy County | J | F | M | A | M | J | J | A | S | O | N | D | Year |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg high °F | 27 | 31 | 45 | 60 | 71 | 81 | 83 | 81 | 76 | 62 | 47 | 32 | 58 |
| Avg low °F | 10 | 14 | 26 | 37 | 48 | 59 | 62 | 59 | 52 | 39 | 28 | 16 | 38 |
| Precip in | 1.0 | 1.1 | 1.9 | 3.6 | 4.9 | 5.6 | 4.2 | 3.9 | 3.0 | 2.9 | 1.6 | 1.4 | 35.1 |
1996–2025 normals for Grundy County — the climate division Reinbeck sits in. All-time county record high 103.1°F (1988-08-18); record low -29.6°F (1996-02-03). Source: NOAA / National Weather Service.