Cass, West Virginia has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 2.5 °C (low) to 15.5 °C (high). Annual precipitation averages 1155.7 Millimeters. Cass is located in USDA Plant Hardiness Zone 6a. The growing season typically runs from the last frost around Apr. 11 - Apr. 20 through the first frost around Oct. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -8 °C | 2.7 °C | 84.33 mm |
| February | -7.1 °C | 4.9 °C | 75.44 mm |
| March | -3.6 °C | 9.3 °C | 99.31 mm |
| April | 1.2 °C | 16.4 °C | 103.38 mm |
| May | 6.7 °C | 20.6 °C | 127.76 mm |
| June | 11.1 °C | 24.4 °C | 113.54 mm |
| July | 13.3 °C | 26.4 °C | 104.14 mm |
| August | 12.8 °C | 26.1 °C | 97.54 mm |
| September | 9.1 °C | 23 °C | 99.82 mm |
| October | 2.7 °C | 16.9 °C | 80.52 mm |
| November | -2.8 °C | 10 °C | 76.2 mm |
| December | -6 °C | 4.9 °C | 93.73 mm |
| Annual | 2.5 °C | 15.5 °C | 1155.71 mm |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | Apr. 11 - Apr. 20 |
| 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 | Abnormally Dry |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |