The official National Weather Service forecast for Ranson — 39.2951°N, 77.8606°W, population 21,569, 11.6 miles from I-81.
| Jefferson County | J | F | M | A | M | J | J | A | S | O | N | D | Year |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg high °F | 42 | 46 | 55 | 66 | 74 | 83 | 87 | 85 | 79 | 67 | 56 | 46 | 66 |
| Avg low °F | 24 | 26 | 32 | 42 | 51 | 60 | 64 | 62 | 56 | 44 | 34 | 28 | 44 |
| Precip in | 2.7 | 2.4 | 3.0 | 3.3 | 4.5 | 4.0 | 4.0 | 3.3 | 4.1 | 3.0 | 2.6 | 3.0 | 39.9 |
1996–2025 normals for Jefferson County — the climate division Ranson sits in. All-time county record high 104.5°F (1988-07-17); record low -12.8°F (1994-01-19). Source: NOAA / National Weather Service.