Westfield, New Jersey has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 44.2 °F (low) to 63.8 °F (high). Annual precipitation averages 48.8 Inches. Westfield is located in USDA Plant Hardiness Zone 7a. The growing season typically runs from the last frost around Apr. 11 - Apr. 20 through the first frost around Oct. 21 - Oct. 31.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 23.1 °F | 39.7 °F | 3.61 in. |
| February | 24.5 °F | 42.5 °F | 2.88 in. |
| March | 31.4 °F | 50.7 °F | 4.24 in. |
| April | 41.7 °F | 62.9 °F | 3.93 in. |
| May | 51.3 °F | 72.8 °F | 4.04 in. |
| June | 60.7 °F | 81.8 °F | 4.57 in. |
| July | 66.0 °F | 86.8 °F | 4.84 in. |
| August | 64.3 °F | 85.0 °F | 4.47 in. |
| September | 57.3 °F | 78.2 °F | 4.32 in. |
| October | 45.4 °F | 66.0 °F | 4.32 in. |
| November | 35.9 °F | 54.9 °F | 3.43 in. |
| December | 28.6 °F | 44.7 °F | 4.19 in. |
| Annual | 44.2 °F | 63.8 °F | 48.84 in. |
| Average First Frost Date | Oct. 21 - Oct. 31 |
| Average Last Frost Date | Apr. 11 - Apr. 20 |
| Average Days With Frost | 100-125 Days |
| Plant Hardiness Zone | Zone 7a : 0°F to 5°F |
| Plant Hardiness Zone - 2012 | Zone 6b : -5°F to 0°F |
| Current Drought Conditions | Severe Drought |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |