New Salem, Massachusetts has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 2 °C (low) to 14.2 °C (high). Annual precipitation averages 1380.5 Millimeters. New Salem is located in USDA Plant Hardiness Zone 5b. 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 | -11 °C | 0 °C | 101.35 mm |
| February | -10.3 °C | 1.7 °C | 90.68 mm |
| March | -5.6 °C | 6.2 °C | 110.24 mm |
| April | 0.6 °C | 13.5 °C | 110.24 mm |
| May | 6.6 °C | 19.8 °C | 101.6 mm |
| June | 11.8 °C | 24.7 °C | 130.05 mm |
| July | 14.9 °C | 27.8 °C | 115.82 mm |
| August | 13.7 °C | 26.9 °C | 128.78 mm |
| September | 9.3 °C | 22.7 °C | 129.29 mm |
| October | 3.1 °C | 15.3 °C | 135.13 mm |
| November | -2.1 °C | 8.8 °C | 104.65 mm |
| December | -7.1 °C | 2.9 °C | 122.68 mm |
| Annual | 2 °C | 14.2 °C | 1380.51 mm |
| 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 5b : -26.1°C to -23.3°C |
| Plant Hardiness Zone - 2012 | Zone 5b : -26.1°C to -23.3°C |
| Current Drought Conditions | Moderate Drought |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |