Northampton, Massachusetts has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 3.6 °C (low) to 15.4 °C (high). Annual precipitation averages 1206.3 Millimeters. 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 | -9.2 °C | 1.1 °C | 84.58 mm |
| February | -8.4 °C | 2.8 °C | 75.95 mm |
| March | -3.7 °C | 7.4 °C | 93.98 mm |
| April | 2.3 °C | 14.9 °C | 98.55 mm |
| May | 8.2 °C | 21.2 °C | 92.96 mm |
| June | 13.3 °C | 25.8 °C | 113.79 mm |
| July | 16.3 °C | 28.7 °C | 102.87 mm |
| August | 15.3 °C | 27.8 °C | 106.93 mm |
| September | 11 °C | 23.8 °C | 116.08 mm |
| October | 4.6 °C | 16.7 °C | 125.48 mm |
| November | -0.8 °C | 10.1 °C | 88.65 mm |
| December | -5.4 °C | 4.2 °C | 106.43 mm |
| Annual | 3.6 °C | 15.4 °C | 1206.25 mm |
| 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 : -23.3°C to -20.6°C |
| Plant Hardiness Zone - 2012 | Zone 6a : -23.3°C to -20.6°C |
| Current Drought Conditions | Moderate Drought |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |