Union Hall, Virginia has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 7.5 °C (low) to 19.9 °C (high). Annual precipitation averages 1160 Millimeters. Union Hall is located in USDA Plant Hardiness Zone 7b. The growing season typically runs from the last frost around Apr. 11 - Apr. 20 through the first frost around Oct. 21 - Oct. 31.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -3.1 °C | 8.1 °C | 92.96 mm |
| February | -2.1 °C | 10.2 °C | 73.91 mm |
| March | 1.4 °C | 14.8 °C | 98.81 mm |
| April | 6.5 °C | 20.7 °C | 97.03 mm |
| May | 11.7 °C | 24.6 °C | 110.49 mm |
| June | 16.3 °C | 28.5 °C | 110.49 mm |
| July | 18.8 °C | 30.4 °C | 102.87 mm |
| August | 18 °C | 29.5 °C | 88.65 mm |
| September | 14.2 °C | 26.1 °C | 116.84 mm |
| October | 7.6 °C | 20.8 °C | 88.14 mm |
| November | 1.7 °C | 15.1 °C | 85.34 mm |
| December | -1.6 °C | 9.8 °C | 94.49 mm |
| Annual | 7.5 °C | 19.9 °C | 1160.02 mm |
| Average First Frost Date | Oct. 21 - Oct. 31 |
| Average Last Frost Date | Apr. 11 - Apr. 20 |
| Average Days With Frost | 100-125 Days |
| Plant Hardiness Zone | Zone 7b : -15°C to -12.2°C |
| Plant Hardiness Zone - 2012 | Zone 7a : -17.8°C to -15°C |
| Current Drought Conditions | Severe Drought |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |