Alderson, West Virginia has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 5.5 °C (low) to 18.5 °C (high). Annual precipitation averages 1046.2 Millimeters. Alderson is located in USDA Plant Hardiness Zone 7a. The growing season typically runs from the last frost around May 1 - May 10 through the first frost around Oct. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -5.3 °C | 5.7 °C | 78.74 mm |
| February | -4.1 °C | 8 °C | 73.15 mm |
| March | -0.6 °C | 13 °C | 96.52 mm |
| April | 4.2 °C | 19.6 °C | 91.95 mm |
| May | 9.7 °C | 23.9 °C | 111.25 mm |
| June | 14.5 °C | 27.5 °C | 100.33 mm |
| July | 16.8 °C | 29.3 °C | 108.71 mm |
| August | 16.2 °C | 28.8 °C | 80.77 mm |
| September | 12.4 °C | 25.6 °C | 84.07 mm |
| October | 5.4 °C | 19.9 °C | 67.06 mm |
| November | -0.4 °C | 13.4 °C | 65.02 mm |
| December | -3.4 °C | 7.4 °C | 88.65 mm |
| Annual | 5.5 °C | 18.5 °C | 1046.22 mm |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | May 1 - May 10 |
| Average Days With Frost | 125-150 Days |
| Plant Hardiness Zone | Zone 7a : -17.8°C to -15°C |
| Plant Hardiness Zone - 2012 | Zone 6b : -20.6°C to -17.8°C |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |