Northampton, Massachusetts has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 38.5 °F (low) to 59.7 °F (high). Annual precipitation averages 47.5 Inches. Northampton is located in USDA Plant Hardiness Zone 6a. The growing season typically runs from the last frost around May 1 - May 10 through the first frost around Oct. 1 - Oct. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 15.4 °F | 34.0 °F | 3.33 in. |
| February | 16.8 °F | 37.0 °F | 2.99 in. |
| March | 25.4 °F | 45.4 °F | 3.7 in. |
| April | 36.2 °F | 58.9 °F | 3.88 in. |
| May | 46.7 °F | 70.2 °F | 3.66 in. |
| June | 55.9 °F | 78.5 °F | 4.48 in. |
| July | 61.3 °F | 83.7 °F | 4.05 in. |
| August | 59.5 °F | 82.0 °F | 4.21 in. |
| September | 51.8 °F | 74.8 °F | 4.57 in. |
| October | 40.3 °F | 62.1 °F | 4.94 in. |
| November | 30.6 °F | 50.2 °F | 3.49 in. |
| December | 22.2 °F | 39.5 °F | 4.19 in. |
| Annual | 38.5 °F | 59.7 °F | 47.49 in. |
| Average First Frost Date | Oct. 1 - Oct. 10 |
| Average Last Frost Date | May 1 - May 10 |
| Average Days With Frost | 125-150 Days |
| Plant Hardiness Zone | Zone 6a : -10°F to -5°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 |