The official National Weather Service forecast for De Graff — 40.312°N, 83.9158°W, 12.9 miles from I-75.
| Logan County | J | F | M | A | M | J | J | A | S | O | N | D | Year |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg high °F | 34 | 38 | 49 | 62 | 72 | 80 | 83 | 82 | 77 | 64 | 50 | 39 | 61 |
| Avg low °F | 19 | 22 | 30 | 39 | 50 | 60 | 63 | 61 | 54 | 43 | 33 | 25 | 42 |
| Precip in | 2.9 | 2.5 | 3.3 | 4.1 | 4.5 | 4.4 | 4.3 | 3.5 | 3.2 | 2.9 | 2.8 | 3.1 | 41.5 |
1996–2025 normals for Logan County — the climate division De Graff sits in. All-time county record high 102.5°F (1988-06-26); record low -23.6°F (1994-01-19). Source: NOAA / National Weather Service.