The official National Weather Service forecast for Mandan — 46.8267°N, 100.8896°W, 2.6 miles from I-94.
| Morton County | J | F | M | A | M | J | J | A | S | O | N | D | Year |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg high °F | 24 | 27 | 40 | 55 | 67 | 77 | 84 | 83 | 74 | 57 | 41 | 27 | 55 |
| Avg low °F | 4 | 7 | 18 | 29 | 41 | 51 | 57 | 55 | 46 | 33 | 19 | 8 | 31 |
| Precip in | 0.4 | 0.5 | 0.7 | 1.4 | 2.7 | 3.2 | 2.4 | 2.2 | 1.6 | 1.4 | 0.6 | 0.6 | 17.7 |
1996–2025 normals for Morton County — the climate division Mandan sits in. All-time county record high 105.5°F (1988-07-28); record low -39.9°F (1966-01-29). Source: NOAA / National Weather Service.