The official National Weather Service forecast for Great Falls — 47.5002°N, 111.3008°W, population 67,097, 2.2 miles from I-15.
| Cascade County | J | F | M | A | M | J | J | A | S | O | N | D | Year |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg high °F | 35 | 35 | 45 | 53 | 62 | 71 | 83 | 81 | 71 | 56 | 43 | 35 | 56 |
| Avg low °F | 15 | 15 | 22 | 29 | 38 | 45 | 51 | 50 | 43 | 33 | 23 | 16 | 32 |
| Precip in | 0.7 | 0.8 | 0.8 | 1.7 | 2.8 | 2.9 | 1.1 | 1.2 | 1.6 | 1.2 | 0.8 | 0.8 | 16.4 |
1996–2025 normals for Cascade County — the climate division Great Falls sits in. All-time county record high 103.1°F (1961-08-06); record low -40.3°F (1983-12-25). Source: NOAA / National Weather Service.