The official National Weather Service forecast for Chillicothe — 39.3331°N, 82.9824°W, population 31,727, 34.3 miles from I-71.
| Ross County | J | F | M | A | M | J | J | A | S | O | N | D | Year |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg high °F | 39 | 43 | 53 | 65 | 74 | 82 | 85 | 84 | 79 | 67 | 54 | 43 | 64 |
| Avg low °F | 23 | 25 | 33 | 41 | 51 | 60 | 64 | 62 | 55 | 44 | 34 | 27 | 43 |
| Precip in | 3.1 | 3.0 | 3.6 | 4.2 | 4.6 | 4.3 | 4.1 | 3.1 | 3.3 | 3.0 | 2.9 | 3.3 | 42.5 |
1996–2025 normals for Ross County — the climate division Chillicothe sits in. All-time county record high 102.1°F (2012-07-08); record low -24.4°F (1994-01-19). Source: NOAA / National Weather Service.