The official National Weather Service forecast for Lake Isabella — 43.6436°N, 84.9972°W, 49.2 miles from I-75. Forecasts here are written by NWS GRR, this county’s forecast office.
| Isabella County | J | F | M | A | M | J | J | A | S | O | N | D | Year |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg high °F | 29 | 33 | 43 | 56 | 69 | 79 | 83 | 80 | 74 | 60 | 46 | 34 | 57 |
| Avg low °F | 15 | 16 | 24 | 34 | 44 | 54 | 58 | 57 | 50 | 39 | 30 | 22 | 37 |
| Precip in | 2.0 | 1.7 | 2.2 | 3.3 | 3.7 | 3.4 | 2.9 | 3.6 | 2.7 | 3.2 | 2.1 | 2.2 | 33.0 |
1996–2025 normals for Isabella County — the climate division Lake Isabella sits in. All-time county record high 100.1°F (1988-07-07); record low -27.5°F (1951-01-30). Source: NOAA / National Weather Service.