The official National Weather Service forecast for Colby — 39.3958°N, 101.0524°W, population 5,467, 2.4 miles from I-70.
| Thomas County | J | F | M | A | M | J | J | A | S | O | N | D | Year |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg high °F | 43 | 46 | 57 | 66 | 75 | 87 | 92 | 89 | 82 | 69 | 56 | 45 | 67 |
| Avg low °F | 17 | 19 | 27 | 35 | 46 | 57 | 63 | 61 | 52 | 38 | 26 | 18 | 38 |
| Precip in | 0.4 | 0.5 | 1.0 | 1.7 | 3.0 | 2.8 | 3.1 | 2.8 | 1.7 | 1.4 | 0.6 | 0.5 | 19.5 |
1996–2025 normals for Thomas County — the climate division Colby sits in. All-time county record high 111.3°F (2012-06-27); record low -27.2°F (1989-12-22). Source: NOAA / National Weather Service.