The official National Weather Service forecast for Mackinac Island — 45.8492°N, 84.6189°W, 5 miles from I-75. Forecasts here are written by NWS APX, this county’s forecast office.
| Mackinac County | J | F | M | A | M | J | J | A | S | O | N | D | Year |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg high °F | 25 | 27 | 36 | 48 | 62 | 72 | 76 | 75 | 68 | 55 | 41 | 31 | 51 |
| Avg low °F | 11 | 10 | 18 | 29 | 40 | 50 | 55 | 55 | 49 | 38 | 28 | 18 | 33 |
| Precip in | 1.9 | 1.6 | 2.1 | 2.7 | 2.7 | 3.3 | 3.2 | 3.2 | 3.5 | 4.0 | 2.9 | 2.6 | 33.7 |
1996–2025 normals for Mackinac County — the climate division Mackinac Island sits in. All-time county record high 93.7°F (1966-07-03); record low -29.7°F (1979-02-18). Source: NOAA / National Weather Service.