Middletown, Delaware has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 45.6 °F (low) to 64.8 °F (high). Annual precipitation averages 44.9 Inches. Middletown 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 | 24.8 °F | 42.1 °F | 3.09 in. |
| February | 25.8 °F | 44.4 °F | 2.7 in. |
| March | 32.9 °F | 52.6 °F | 4.03 in. |
| April | 43.2 °F | 64.0 °F | 3.56 in. |
| May | 52.8 °F | 73.2 °F | 3.77 in. |
| June | 62.3 °F | 81.9 °F | 4.57 in. |
| July | 67.4 °F | 86.3 °F | 4.25 in. |
| August | 65.8 °F | 84.5 °F | 3.88 in. |
| September | 59.1 °F | 78.5 °F | 4.22 in. |
| October | 47.1 °F | 67.1 °F | 3.89 in. |
| November | 36.7 °F | 56.2 °F | 3.03 in. |
| December | 29.8 °F | 46.3 °F | 3.87 in. |
| Annual | 45.6 °F | 64.8 °F | 44.86 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 | Severe Drought |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |