Keswick, Virginia has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 6.9 °C (low) to 19.7 °C (high). Annual precipitation averages 1159.8 Millimeters. Keswick is located in USDA Plant Hardiness Zone 7a. The growing season typically runs from the last frost around Apr. 1 - Apr. 10 through the first frost around Nov. 1 - Nov. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -4.1 °C | 7.6 °C | 78.74 mm |
| February | -3.1 °C | 9.4 °C | 69.09 mm |
| March | 0.4 °C | 14.1 °C | 99.31 mm |
| April | 5.9 °C | 20.4 °C | 86.36 mm |
| May | 11.2 °C | 24.4 °C | 112.52 mm |
| June | 16.2 °C | 28.8 °C | 114.3 mm |
| July | 18.5 °C | 30.8 °C | 111.25 mm |
| August | 17.7 °C | 29.9 °C | 95.76 mm |
| September | 13.9 °C | 26.4 °C | 119.63 mm |
| October | 7.1 °C | 20.7 °C | 97.03 mm |
| November | 1.2 °C | 14.7 °C | 86.87 mm |
| December | -2.2 °C | 9.4 °C | 88.9 mm |
| Annual | 6.9 °C | 19.7 °C | 1159.76 mm |
| Average First Frost Date | Nov. 1 - Nov. 10 |
| Average Last Frost Date | Apr. 1 - Apr. 10 |
| Average Days With Frost | 75-100 Days |
| Plant Hardiness Zone | Zone 7a : -17.8°C to -15°C |
| Plant Hardiness Zone - 2012 | Zone 7a : -17.8°C to -15°C |
| Current Drought Conditions | Extreme Drought |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |