McLean, Virginia has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 8.5 °C (low) to 19.2 °C (high). Annual precipitation averages 1163.3 Millimeters. McLean is located in USDA Plant Hardiness Zone 7b. 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 | -2.8 °C | 6.4 °C | 79.5 mm |
| February | -2.1 °C | 8.3 °C | 70.36 mm |
| March | 1.7 °C | 12.9 °C | 100.33 mm |
| April | 7.2 °C | 19.6 °C | 87.63 mm |
| May | 12.6 °C | 24.1 °C | 115.32 mm |
| June | 17.7 °C | 28.7 °C | 113.54 mm |
| July | 20.3 °C | 31.1 °C | 117.09 mm |
| August | 19.4 °C | 30.1 °C | 92.2 mm |
| September | 15.7 °C | 26.4 °C | 113.79 mm |
| October | 9.1 °C | 19.9 °C | 99.57 mm |
| November | 3.3 °C | 14 °C | 81.28 mm |
| December | -0.4 °C | 8.6 °C | 92.71 mm |
| Annual | 8.5 °C | 19.2 °C | 1163.32 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 7b : -15°C to -12.2°C |
| Plant Hardiness Zone - 2012 | Zone 7a : -17.8°C to -15°C |
| Current Drought Conditions | Moderate Drought |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |