Wellsburg, New York has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 2.6 °C (low) to 15.2 °C (high). Annual precipitation averages 915.7 Millimeters. Wellsburg is located in USDA Plant Hardiness Zone 6a. The growing season typically runs from the last frost around May 1 - May 10 through the first frost around Oct. 1 - Oct. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -9.2 °C | 0.9 °C | 51.56 mm |
| February | -9 °C | 2.2 °C | 43.43 mm |
| March | -4.9 °C | 7 °C | 68.58 mm |
| April | 0.7 °C | 14.7 °C | 83.57 mm |
| May | 6.9 °C | 21.4 °C | 77.47 mm |
| June | 12.1 °C | 26.1 °C | 102.87 mm |
| July | 14.3 °C | 28.6 °C | 89.66 mm |
| August | 13.7 °C | 27.7 °C | 89.15 mm |
| September | 9.8 °C | 23.9 °C | 97.79 mm |
| October | 3.5 °C | 16.4 °C | 87.63 mm |
| November | -1.5 °C | 9.4 °C | 62.23 mm |
| December | -5.4 °C | 3.5 °C | 61.72 mm |
| Annual | 2.6 °C | 15.2 °C | 915.66 mm |
| Average First Frost Date | Oct. 1 - Oct. 10 |
| Average Last Frost Date | May 1 - May 10 |
| Average Days With Frost | 125-150 Days |
| Plant Hardiness Zone | Zone 6a : -23.3°C to -20.6°C |
| Plant Hardiness Zone - 2012 | Zone 5b : -26.1°C to -23.3°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |