Dover, Delaware has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 8 °C (low) to 18.4 °C (high). Annual precipitation averages 1166.4 Millimeters. Dover 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 | -3.5 °C | 6.2 °C | 86.36 mm |
| February | -2.9 °C | 7.4 °C | 76.45 mm |
| March | 1.1 °C | 11.6 °C | 105.92 mm |
| April | 6.7 °C | 17.8 °C | 91.69 mm |
| May | 11.9 °C | 22.7 °C | 97.54 mm |
| June | 17.2 °C | 27.6 °C | 106.68 mm |
| July | 20.1 °C | 30.2 °C | 104.39 mm |
| August | 19.1 °C | 29.1 °C | 120.4 mm |
| September | 15.3 °C | 25.9 °C | 98.55 mm |
| October | 8.8 °C | 19.8 °C | 98.04 mm |
| November | 2.9 °C | 13.9 °C | 81.28 mm |
| December | -0.8 °C | 8.7 °C | 99.06 mm |
| Annual | 8 °C | 18.4 °C | 1166.36 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 | Extreme Drought |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |