Fenwick Island, Delaware has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 9.9 °C (low) to 17.8 °C (high). Annual precipitation averages 1245.6 Millimeters. Fenwick Island is located in USDA Plant Hardiness Zone 8a. 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 | -1.1 °C | 6.9 °C | 95.76 mm |
| February | -0.6 °C | 7.8 °C | 78.74 mm |
| March | 2.7 °C | 10.8 °C | 113.28 mm |
| April | 7.8 °C | 16.3 °C | 92.2 mm |
| May | 12.9 °C | 20.8 °C | 96.52 mm |
| June | 18.4 °C | 25.8 °C | 96.77 mm |
| July | 21.3 °C | 28.8 °C | 115.06 mm |
| August | 20.9 °C | 27.9 °C | 124.97 mm |
| September | 18.1 °C | 25.1 °C | 108.46 mm |
| October | 11.7 °C | 19.9 °C | 120.65 mm |
| November | 5.7 °C | 14.1 °C | 92.71 mm |
| December | 1.4 °C | 9.4 °C | 110.49 mm |
| Annual | 9.9 °C | 17.8 °C | 1245.61 mm |
| Average First Frost Date | Nov. 1 - Nov. 10 |
| Average Last Frost Date | Apr. 1 - Apr. 10 |
| Average Days With Frost | 50-75 Days |
| Plant Hardiness Zone | Zone 8a : -12.2°C to -9.4°C |
| Plant Hardiness Zone - 2012 | Zone 7b : -15°C to -12.2°C |
| Current Drought Conditions | Severe Drought |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |