The official National Weather Service forecast for Ann Arbor — 42.2776°N, 83.7409°W, population 317,689, 2.4 miles from I-94. Forecasts here are written by NWS DTX, this county’s forecast office.
| Washtenaw County | J | F | M | A | M | J | J | A | S | O | N | D | Year |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg high °F | 31 | 35 | 46 | 59 | 70 | 79 | 83 | 81 | 75 | 62 | 48 | 37 | 59 |
| Avg low °F | 17 | 18 | 26 | 36 | 47 | 57 | 60 | 59 | 52 | 41 | 31 | 23 | 39 |
| Precip in | 2.1 | 1.9 | 2.4 | 3.2 | 3.9 | 3.7 | 3.3 | 3.3 | 2.9 | 2.7 | 2.3 | 2.2 | 33.9 |
1996–2025 normals for Washtenaw County — the climate division Ann Arbor sits in. All-time county record high 100.7°F (2012-07-18); record low -20.1°F (1994-01-19). Source: NOAA / National Weather Service.