Glen Jean, West Virginia has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 5.3 °C (low) to 17.4 °C (high). Annual precipitation averages 1188 Millimeters. Glen Jean 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 | -5.5 °C | 4.8 °C | 84.07 mm |
| February | -4.3 °C | 7 °C | 83.06 mm |
| March | -1.1 °C | 11.7 °C | 108.2 mm |
| April | 4.2 °C | 18.7 °C | 105.16 mm |
| May | 9.4 °C | 22.8 °C | 123.44 mm |
| June | 14.2 °C | 26.2 °C | 124.21 mm |
| July | 16.3 °C | 27.8 °C | 129.29 mm |
| August | 15.7 °C | 27.4 °C | 98.55 mm |
| September | 12.1 °C | 24.4 °C | 91.69 mm |
| October | 5.4 °C | 18.6 °C | 71.88 mm |
| November | -0.1 °C | 12.2 °C | 74.17 mm |
| December | -3.1 °C | 6.8 °C | 94.23 mm |
| Annual | 5.3 °C | 17.4 °C | 1187.95 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 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 |