Westhampton, Massachusetts has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 36 °F (low) to 57.7 °F (high). Annual precipitation averages 51.1 Inches. Westhampton is located in USDA Plant Hardiness Zone 6a. The growing season typically runs from the last frost around May 11 - May 20 through the first frost around Oct. 1 - Oct. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 12.9 °F | 32.1 °F | 3.56 in. |
| February | 14.1 °F | 34.9 °F | 3.31 in. |
| March | 22.5 °F | 43.2 °F | 4.05 in. |
| April | 33.4 °F | 56.7 °F | 4.16 in. |
| May | 44.3 °F | 68.3 °F | 4.08 in. |
| June | 53.6 °F | 76.5 °F | 4.65 in. |
| July | 58.9 °F | 81.7 °F | 4.3 in. |
| August | 56.9 °F | 79.9 °F | 4.4 in. |
| September | 49.2 °F | 72.8 °F | 4.83 in. |
| October | 38.2 °F | 60.4 °F | 5.24 in. |
| November | 28.5 °F | 48.2 °F | 3.93 in. |
| December | 19.7 °F | 37.3 °F | 4.54 in. |
| Annual | 36 °F | 57.7 °F | 51.05 in. |
| Average First Frost Date | Oct. 1 - Oct. 10 |
| Average Last Frost Date | May 11 - May 20 |
| Average Days With Frost | 125-150 Days |
| Plant Hardiness Zone | Zone 6a : -10°F to -5°F |
| Plant Hardiness Zone - 2012 | Zone 5b : -15°F to -10°F |
| Current Drought Conditions | Moderate Drought |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |