Chantilly, Virginia has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 45.2 °F (low) to 66.1 °F (high). Annual precipitation averages 44 Inches. Chantilly 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. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 24.8 °F | 43.1 °F | 2.98 in. |
| February | 26.3 °F | 46.3 °F | 2.61 in. |
| March | 33.2 °F | 54.8 °F | 3.71 in. |
| April | 43.2 °F | 66.6 °F | 3.28 in. |
| May | 52.9 °F | 74.7 °F | 4.46 in. |
| June | 62.0 °F | 83.2 °F | 4.41 in. |
| July | 66.8 °F | 87.7 °F | 4.3 in. |
| August | 65.0 °F | 86.0 °F | 3.55 in. |
| September | 58.2 °F | 79.4 °F | 4.19 in. |
| October | 45.8 °F | 67.9 °F | 3.75 in. |
| November | 35.5 °F | 56.9 °F | 3.17 in. |
| December | 28.9 °F | 47.0 °F | 3.55 in. |
| Annual | 45.2 °F | 66.1 °F | 43.96 in. |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | Apr. 11 - Apr. 20 |
| Average Days With Frost | 100-125 Days |
| Plant Hardiness Zone | Zone 7b : 5°F to 10°F |
| Plant Hardiness Zone - 2012 | Zone 7a : 0°F to 5°F |
| Current Drought Conditions | Moderate Drought |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |