New Boston, New Hampshire has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 36.4 °F (low) to 57.6 °F (high). Annual precipitation averages 48.1 Inches. New Boston 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 | 13.2 °F | 32.0 °F | 3.36 in. |
| February | 14.4 °F | 35.0 °F | 3.35 in. |
| March | 22.7 °F | 43.1 °F | 3.89 in. |
| April | 33.6 °F | 56.5 °F | 3.93 in. |
| May | 44.7 °F | 67.7 °F | 3.74 in. |
| June | 54.2 °F | 76.6 °F | 4.56 in. |
| July | 59.5 °F | 81.6 °F | 3.85 in. |
| August | 57.5 °F | 80.2 °F | 3.79 in. |
| September | 50.0 °F | 72.9 °F | 4.11 in. |
| October | 38.4 °F | 59.8 °F | 4.99 in. |
| November | 29.2 °F | 48.4 °F | 3.99 in. |
| December | 19.7 °F | 37.5 °F | 4.49 in. |
| Annual | 36.4 °F | 57.6 °F | 48.05 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 5b : -15°F to -10°F |
| Current Drought Conditions | Moderate Drought |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |