Morristown, New Jersey has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 42.3 °F (low) to 62.3 °F (high). Annual precipitation averages 50 Inches. Morristown is located in USDA Plant Hardiness Zone 7a. The growing season typically runs from the last frost around Apr. 21 - Apr. 30 through the first frost around Oct. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 21.0 °F | 38.2 °F | 3.78 in. |
| February | 22.2 °F | 40.7 °F | 2.82 in. |
| March | 29.5 °F | 49.0 °F | 4.28 in. |
| April | 40.1 °F | 61.4 °F | 4.07 in. |
| May | 49.8 °F | 71.4 °F | 4.13 in. |
| June | 58.9 °F | 80.2 °F | 4.85 in. |
| July | 64.0 °F | 85.3 °F | 4.66 in. |
| August | 62.4 °F | 83.5 °F | 4.57 in. |
| September | 55.0 °F | 76.7 °F | 4.43 in. |
| October | 43.4 °F | 64.7 °F | 4.43 in. |
| November | 34.0 °F | 53.4 °F | 3.6 in. |
| December | 26.7 °F | 43.2 °F | 4.4 in. |
| Annual | 42.3 °F | 62.3 °F | 50.02 in. |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | Apr. 21 - Apr. 30 |
| Average Days With Frost | 100-125 Days |
| Plant Hardiness Zone | Zone 7a : 0°F to 5°F |
| Plant Hardiness Zone - 2012 | Zone 6a : -10°F to -5°F |
| Current Drought Conditions | Moderate Drought |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |