Dover, New Hampshire has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 36.8 °F (low) to 57.9 °F (high). Annual precipitation averages 45.3 Inches. Dover 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 | 14.4 °F | 33.2 °F | 3.06 in. |
| February | 16.1 °F | 35.9 °F | 3.11 in. |
| March | 23.9 °F | 43.5 °F | 3.83 in. |
| April | 33.9 °F | 55.9 °F | 4.15 in. |
| May | 44.0 °F | 66.5 °F | 3.64 in. |
| June | 53.3 °F | 75.9 °F | 4.07 in. |
| July | 59.3 °F | 81.6 °F | 3.82 in. |
| August | 57.6 °F | 80.7 °F | 3.49 in. |
| September | 49.9 °F | 73.2 °F | 3.65 in. |
| October | 38.5 °F | 60.8 °F | 4.54 in. |
| November | 29.9 °F | 49.3 °F | 3.78 in. |
| December | 21.2 °F | 38.3 °F | 4.17 in. |
| Annual | 36.8 °F | 57.9 °F | 45.31 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 | Severe Drought |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |