Grafton, West Virginia has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 41.6 °F (low) to 63.4 °F (high). Annual precipitation averages 48.5 Inches. Grafton is located in USDA Plant Hardiness Zone 6b. The growing season typically runs from the last frost around Apr. 21 - Apr. 30 through the first frost around Oct. 21 - Oct. 31.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 21.7 °F | 39.8 °F | 3.66 in. |
| February | 23.4 °F | 43.1 °F | 3.34 in. |
| March | 29.9 °F | 52.3 °F | 4.03 in. |
| April | 39.6 °F | 65.1 °F | 4.01 in. |
| May | 49.3 °F | 73.0 °F | 4.93 in. |
| June | 57.9 °F | 80.1 °F | 4.61 in. |
| July | 62.1 °F | 83.3 °F | 5.63 in. |
| August | 60.7 °F | 82.6 °F | 4.14 in. |
| September | 53.8 °F | 77.4 °F | 3.74 in. |
| October | 42.0 °F | 65.8 °F | 3.34 in. |
| November | 32.6 °F | 53.9 °F | 3.07 in. |
| December | 26.4 °F | 43.8 °F | 3.97 in. |
| Annual | 41.6 °F | 63.4 °F | 48.47 in. |
| Average First Frost Date | Oct. 21 - Oct. 31 |
| Average Last Frost Date | Apr. 21 - Apr. 30 |
| Average Days With Frost | 100-125 Days |
| Plant Hardiness Zone | Zone 6b : -5°F to 0°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 |