Alexandria, Virginia has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 9.5 °C (low) to 19.5 °C (high). Annual precipitation averages 1140.5 Millimeters. Alexandria is located in USDA Plant Hardiness Zone 8a. The growing season typically runs from the last frost around Mar. 21 - Mar. 31 through the first frost around Nov. 11 - Nov. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -2 °C | 6.8 °C | 77.98 mm |
| February | -1.1 °C | 8.7 °C | 67.56 mm |
| March | 2.6 °C | 13.2 °C | 97.03 mm |
| April | 8.3 °C | 19.6 °C | 86.87 mm |
| May | 13.6 °C | 24.2 °C | 112.78 mm |
| June | 18.8 °C | 29 °C | 114.81 mm |
| July | 21.4 °C | 31.5 °C | 116.84 mm |
| August | 20.5 °C | 30.5 °C | 91.69 mm |
| September | 16.8 °C | 26.8 °C | 106.93 mm |
| October | 10.2 °C | 20.5 °C | 97.28 mm |
| November | 4.4 °C | 14.3 °C | 76.96 mm |
| December | 0.4 °C | 9.1 °C | 93.73 mm |
| Annual | 9.5 °C | 19.5 °C | 1140.46 mm |
| Average First Frost Date | Nov. 11 - Nov. 20 |
| Average Last Frost Date | Mar. 21 - Mar. 31 |
| Average Days With Frost | 50-75 Days |
| Plant Hardiness Zone | Zone 8a : -12.2°C to -9.4°C |
| Plant Hardiness Zone - 2012 | Zone 7b : -15°C to -12.2°C |
| Current Drought Conditions | Severe Drought |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |