Sussex, New Jersey has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 38.7 °F (low) to 60.7 °F (high). Annual precipitation averages 46 Inches. Sussex is located in USDA Plant Hardiness Zone 6b. The growing season typically runs from the last frost around Apr. 21 - Apr. 30 through the first frost around Oct. 1 - Oct. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 16.8 °F | 35.6 °F | 3.25 in. |
| February | 18.2 °F | 38.9 °F | 2.72 in. |
| March | 25.8 °F | 47.3 °F | 3.86 in. |
| April | 36.4 °F | 60.4 °F | 3.84 in. |
| May | 46.7 °F | 71.0 °F | 3.45 in. |
| June | 55.9 °F | 79.0 °F | 4.65 in. |
| July | 60.7 °F | 83.8 °F | 4.04 in. |
| August | 59.0 °F | 81.8 °F | 4.44 in. |
| September | 51.6 °F | 75.4 °F | 4.14 in. |
| October | 40.2 °F | 63.4 °F | 4.35 in. |
| November | 30.1 °F | 51.5 °F | 3.31 in. |
| December | 23.0 °F | 40.7 °F | 3.99 in. |
| Annual | 38.7 °F | 60.7 °F | 46.04 in. |
| Average First Frost Date | Oct. 1 - Oct. 10 |
| Average Last Frost Date | Apr. 21 - Apr. 30 |
| Average Days With Frost | 125-150 Days |
| Plant Hardiness Zone | Zone 6b : -5°F to 0°F |
| Plant Hardiness Zone - 2012 | Zone 6a : -10°F to -5°F |
| Current Drought Conditions | Moderate Drought |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |