Dewey Beach, Delaware has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 49.6 °F (low) to 64.3 °F (high). Annual precipitation averages 46.9 Inches. Dewey Beach 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 | 29.6 °F | 43.8 °F | 3.46 in. |
| February | 30.4 °F | 45.3 °F | 3.13 in. |
| March | 36.8 °F | 51.1 °F | 4.2 in. |
| April | 46.1 °F | 61.8 °F | 3.45 in. |
| May | 55.3 °F | 70.3 °F | 3.58 in. |
| June | 65.1 °F | 79.4 °F | 3.76 in. |
| July | 70.2 °F | 84.8 °F | 4.61 in. |
| August | 69.3 °F | 83.1 °F | 4.58 in. |
| September | 64.0 °F | 77.7 °F | 4.13 in. |
| October | 52.6 °F | 67.9 °F | 4.45 in. |
| November | 41.8 °F | 57.1 °F | 3.44 in. |
| December | 34.2 °F | 48.8 °F | 4.15 in. |
| Annual | 49.6 °F | 64.3 °F | 46.94 in. |
| 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 : 10°F to 15°F |
| Plant Hardiness Zone - 2012 | Zone 7b : 5°F to 10°F |
| Current Drought Conditions | Extreme Drought |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |