Terra Alta, West Virginia has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 4 °C (low) to 14.6 °C (high). Annual precipitation averages 1414.5 Millimeters. Terra Alta is located in USDA Plant Hardiness Zone 6b. 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 | -7.3 °C | 1.4 °C | 115.06 mm |
| February | -6.2 °C | 3.3 °C | 104.65 mm |
| March | -2.7 °C | 7.9 °C | 119.38 mm |
| April | 3 °C | 15.5 °C | 121.16 mm |
| May | 8.5 °C | 20.1 °C | 138.68 mm |
| June | 13.1 °C | 24 °C | 137.41 mm |
| July | 15.1 °C | 25.8 °C | 149.1 mm |
| August | 14.4 °C | 25.3 °C | 119.89 mm |
| September | 10.8 °C | 22.4 °C | 103.38 mm |
| October | 4.7 °C | 16.2 °C | 95.5 mm |
| November | -0.6 °C | 9.4 °C | 95 mm |
| December | -4.6 °C | 3.9 °C | 115.32 mm |
| Annual | 4 °C | 14.6 °C | 1414.53 mm |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | May 1 - May 10 |
| Average Days With Frost | 100-125 Days |
| Plant Hardiness Zone | Zone 6b : -20.6°C to -17.8°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 |