Delaware City, Delaware has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 7.9 °C (low) to 17.8 °C (high). Annual precipitation averages 1168.2 Millimeters. Delaware City 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 | -3.8 °C | 5.1 °C | 84.84 mm |
| February | -3.2 °C | 6.4 °C | 72.64 mm |
| March | 0.8 °C | 10.8 °C | 105.66 mm |
| April | 6.5 °C | 17.4 °C | 91.19 mm |
| May | 12 °C | 22.7 °C | 94.49 mm |
| June | 17.3 °C | 27.4 °C | 115.82 mm |
| July | 20.1 °C | 29.9 °C | 114.05 mm |
| August | 19.3 °C | 28.9 °C | 104.9 mm |
| September | 15.6 °C | 25.7 °C | 106.93 mm |
| October | 8.8 °C | 19.2 °C | 98.3 mm |
| November | 2.9 °C | 13 °C | 77.98 mm |
| December | -1 °C | 7.6 °C | 101.35 mm |
| Annual | 7.9 °C | 17.8 °C | 1168.15 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 | Abnormally Dry |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |