De Graff, Ohio has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 41.5 °F (low) to 60.7 °F (high). Annual precipitation averages 41.8 Inches. De Graff is located in USDA Plant Hardiness Zone 6a. The growing season typically runs from the last frost around Apr. 21 - Apr. 30 through the first frost around Oct. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 19.1 °F | 34.2 °F | 2.95 in. |
| February | 21.0 °F | 37.8 °F | 2.33 in. |
| March | 29.3 °F | 48.1 °F | 3.17 in. |
| April | 39.5 °F | 61.1 °F | 4.14 in. |
| May | 50.8 °F | 71.6 °F | 4.4 in. |
| June | 60.0 °F | 80.3 °F | 4.64 in. |
| July | 62.9 °F | 83.5 °F | 4.54 in. |
| August | 61.1 °F | 82.1 °F | 3.48 in. |
| September | 53.9 °F | 76.7 °F | 3.18 in. |
| October | 42.7 °F | 64.2 °F | 2.83 in. |
| November | 32.6 °F | 50.3 °F | 3.11 in. |
| December | 24.7 °F | 39.0 °F | 3.02 in. |
| Annual | 41.5 °F | 60.7 °F | 41.79 in. |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | Apr. 21 - Apr. 30 |
| Average Days With Frost | 100-125 Days |
| Plant Hardiness Zone | Zone 6a : -10°F to -5°F |
| Plant Hardiness Zone - 2012 | Zone 6a : -10°F to -5°F |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |