Hanover, New Hampshire has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 34.2 °F (low) to 56.5 °F (high). Annual precipitation averages 39.5 Inches. Hanover is located in USDA Plant Hardiness Zone 5a. 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 | 8.6 °F | 28.9 °F | 2.71 in. |
| February | 10.1 °F | 32.5 °F | 2.41 in. |
| March | 19.3 °F | 41.4 °F | 3.07 in. |
| April | 31.4 °F | 55.7 °F | 3.2 in. |
| May | 43.3 °F | 68.6 °F | 3.15 in. |
| June | 52.4 °F | 76.8 °F | 3.57 in. |
| July | 58.0 °F | 81.8 °F | 4.24 in. |
| August | 56.1 °F | 80.2 °F | 3.32 in. |
| September | 48.6 °F | 72.9 °F | 3.45 in. |
| October | 37.1 °F | 58.8 °F | 4.01 in. |
| November | 27.5 °F | 46.2 °F | 3.01 in. |
| December | 17.5 °F | 34.2 °F | 3.32 in. |
| Annual | 34.2 °F | 56.5 °F | 39.46 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 5a : -20°F to -15°F |
| Plant Hardiness Zone - 2012 | Zone 5a : -20°F to -15°F |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |