The official National Weather Service forecast for Gillette — 44.2911°N, 105.5022°W, population 34,422, 0.8 miles from I-90.
| Campbell County | J | F | M | A | M | J | J | A | S | O | N | D | Year |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg high °F | 34 | 36 | 48 | 55 | 65 | 77 | 87 | 85 | 76 | 59 | 46 | 35 | 59 |
| Avg low °F | 13 | 14 | 22 | 29 | 39 | 48 | 56 | 53 | 44 | 32 | 21 | 13 | 32 |
| Precip in | 0.4 | 0.6 | 0.9 | 1.7 | 2.8 | 2.2 | 1.6 | 1.2 | 1.1 | 1.3 | 0.5 | 0.5 | 14.8 |
1996–2025 normals for Campbell County — the climate division Gillette sits in. All-time county record high 104.5°F (2026-07-13); record low -37.4°F (1983-12-24). Source: NOAA / National Weather Service.