Wellsville, Ohio has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 5.7 °C (low) to 16.6 °C (high). Annual precipitation averages 1052.6 Millimeters. Wellsville is located in USDA Plant Hardiness Zone 7a. 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 | -5.8 °C | 2.7 °C | 81.03 mm |
| February | -5.2 °C | 4.5 °C | 61.72 mm |
| March | -1.3 °C | 9.5 °C | 85.34 mm |
| April | 4.1 °C | 17.3 °C | 94.49 mm |
| May | 9.9 °C | 22.3 °C | 99.82 mm |
| June | 14.8 °C | 26.9 °C | 111.76 mm |
| July | 17.3 °C | 28.8 °C | 108.2 mm |
| August | 16.5 °C | 28.2 °C | 90.68 mm |
| September | 12.9 °C | 24.7 °C | 90.93 mm |
| October | 6.7 °C | 17.9 °C | 76.71 mm |
| November | 1.2 °C | 10.9 °C | 73.15 mm |
| December | -2.8 °C | 5.2 °C | 78.74 mm |
| Annual | 5.7 °C | 16.6 °C | 1052.57 mm |
| 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 7a : -17.8°C to -15°C |
| Plant Hardiness Zone - 2012 | Zone 6a : -23.3°C to -20.6°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |