Amherst, New Hampshire has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 37 °F (low) to 58.7 °F (high). Annual precipitation averages 47.2 Inches. Amherst 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. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 13.9 °F | 33.4 °F | 3.36 in. |
| February | 15.3 °F | 36.3 °F | 3.2 in. |
| March | 23.5 °F | 44.2 °F | 3.83 in. |
| April | 34.3 °F | 57.5 °F | 4.02 in. |
| May | 45.3 °F | 68.6 °F | 3.72 in. |
| June | 54.6 °F | 77.5 °F | 4.43 in. |
| July | 60.1 °F | 82.8 °F | 3.84 in. |
| August | 58.2 °F | 81.2 °F | 3.75 in. |
| September | 50.5 °F | 73.8 °F | 4.05 in. |
| October | 38.6 °F | 60.9 °F | 4.87 in. |
| November | 29.4 °F | 49.5 °F | 3.79 in. |
| December | 20.4 °F | 38.8 °F | 4.36 in. |
| Annual | 37 °F | 58.7 °F | 47.22 in. |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| 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 5b : -15°F to -10°F |
| Current Drought Conditions | Moderate Drought |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |