The official National Weather Service forecast for Grand River — 41.7362°N, 81.2812°W, 6 miles from I-90.
| Lake County | J | F | M | A | M | J | J | A | S | O | N | D | Year |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg high °F | 34 | 37 | 46 | 58 | 69 | 78 | 81 | 80 | 74 | 63 | 50 | 40 | 59 |
| Avg low °F | 21 | 21 | 29 | 38 | 49 | 59 | 63 | 62 | 56 | 45 | 35 | 27 | 42 |
| Precip in | 3.0 | 2.4 | 3.0 | 3.7 | 3.8 | 4.0 | 4.1 | 3.9 | 4.0 | 4.1 | 3.4 | 3.3 | 42.7 |
1996–2025 normals for Lake County — the climate division Grand River sits in. All-time county record high 96.9°F (1988-07-17); record low -20.1°F (2015-02-20). Source: NOAA / National Weather Service.