Chesterfield, New Hampshire has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 35.8 °F (low) to 56.2 °F (high). Annual precipitation averages 48.7 Inches. Chesterfield is located in USDA Plant Hardiness Zone 6a. The growing season typically runs from the last frost around May 11 - May 20 through the first frost around Sep. 21 - Sep. 30.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 12.9 °F | 30.5 °F | 3.47 in. |
| February | 14.3 °F | 33.5 °F | 3.06 in. |
| March | 21.9 °F | 41.4 °F | 3.62 in. |
| April | 33.0 °F | 54.8 °F | 3.75 in. |
| May | 43.6 °F | 66.8 °F | 3.9 in. |
| June | 53.4 °F | 75.2 °F | 4.55 in. |
| July | 59.1 °F | 80.2 °F | 4.44 in. |
| August | 56.2 °F | 78.8 °F | 4.44 in. |
| September | 49.0 °F | 71.4 °F | 4.28 in. |
| October | 37.9 °F | 58.6 °F | 5.09 in. |
| November | 29.0 °F | 46.9 °F | 3.73 in. |
| December | 19.5 °F | 36.1 °F | 4.35 in. |
| Annual | 35.8 °F | 56.2 °F | 48.68 in. |
| Average First Frost Date | Sep. 21 - Sep. 30 |
| Average Last Frost Date | May 11 - May 20 |
| Average Days With Frost | 150-180 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 | Abnormally Dry |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |