Henderson, Maryland has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 45.4 °F (low) to 65.5 °F (high). Annual precipitation averages 47.1 Inches. Henderson 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 | 25.0 °F | 43.1 °F | 3.52 in. |
| February | 26.1 °F | 45.3 °F | 3.19 in. |
| March | 33.2 °F | 53.1 °F | 4.08 in. |
| April | 43.4 °F | 64.7 °F | 3.64 in. |
| May | 53.0 °F | 73.6 °F | 4.04 in. |
| June | 62.0 °F | 82.3 °F | 4.49 in. |
| July | 67.0 °F | 86.8 °F | 4.34 in. |
| August | 64.9 °F | 85.1 °F | 4.36 in. |
| September | 58.3 °F | 79.4 °F | 4.16 in. |
| October | 46.1 °F | 68.1 °F | 4.0 in. |
| November | 36.0 °F | 57.2 °F | 3.27 in. |
| December | 29.6 °F | 47.6 °F | 3.97 in. |
| Annual | 45.4 °F | 65.5 °F | 47.06 in. |
| 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 : 5°F to 10°F |
| Plant Hardiness Zone - 2012 | Zone 7a : 0°F to 5°F |
| Current Drought Conditions | Extreme Drought |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |