The official National Weather Service forecast for Derby — 39.7687°N, 83.2057°W, 2.4 miles from I-71.
| Pickaway County | J | F | M | A | M | J | J | A | S | O | N | D | Year |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg high °F | 38 | 42 | 53 | 65 | 74 | 82 | 85 | 84 | 79 | 67 | 53 | 43 | 64 |
| Avg low °F | 22 | 24 | 32 | 41 | 52 | 60 | 64 | 62 | 55 | 44 | 34 | 27 | 43 |
| Precip in | 2.9 | 2.8 | 3.4 | 4.1 | 4.5 | 4.6 | 4.1 | 3.3 | 3.0 | 2.9 | 2.9 | 3.1 | 41.6 |
1996–2025 normals for Pickaway County — the climate division Derby sits in. All-time county record high 101.6°F (1988-06-26); record low -24.0°F (1994-01-19). Source: NOAA / National Weather Service.