Andover, 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 56.3 °F (high). Annual precipitation averages 47.6 Inches. Andover is located in USDA Plant Hardiness Zone 5b. 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 | 10.3 °F | 29.7 °F | 3.21 in. |
| February | 11.3 °F | 32.8 °F | 2.98 in. |
| March | 20.1 °F | 41.3 °F | 3.45 in. |
| April | 31.5 °F | 55.0 °F | 3.84 in. |
| May | 42.7 °F | 67.5 °F | 3.88 in. |
| June | 51.9 °F | 76.1 °F | 4.47 in. |
| July | 57.6 °F | 81.4 °F | 4.41 in. |
| August | 55.4 °F | 79.7 °F | 3.99 in. |
| September | 47.8 °F | 72.1 °F | 3.88 in. |
| October | 36.4 °F | 58.7 °F | 5.34 in. |
| November | 27.5 °F | 46.2 °F | 3.91 in. |
| December | 17.9 °F | 35.3 °F | 4.28 in. |
| Annual | 34.2 °F | 56.3 °F | 47.64 in. |
| Average First Frost Date | Oct. 1 - Oct. 10 |
| Average Last Frost Date | May 1 - May 10 |
| Average Days With Frost | 150-180 Days |
| Plant Hardiness Zone | Zone 5b : -15°F to -10°F |
| Plant Hardiness Zone - 2012 | Zone 5a : -20°F to -15°F |
| Current Drought Conditions | Moderate Drought |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |