Seabrook, New Hampshire has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 39 °F (low) to 58.3 °F (high). Annual precipitation averages 49.9 Inches. Seabrook is located in USDA Plant Hardiness Zone 6b. 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 | 16.8 °F | 34.5 °F | 3.77 in. |
| February | 18.1 °F | 37.0 °F | 3.64 in. |
| March | 25.8 °F | 44.1 °F | 4.68 in. |
| April | 35.4 °F | 56.2 °F | 4.37 in. |
| May | 45.6 °F | 66.0 °F | 4.15 in. |
| June | 55.6 °F | 75.7 °F | 4.46 in. |
| July | 61.5 °F | 81.8 °F | 3.56 in. |
| August | 60.0 °F | 80.6 °F | 3.55 in. |
| September | 52.7 °F | 73.2 °F | 3.98 in. |
| October | 41.3 °F | 60.9 °F | 5.01 in. |
| November | 31.9 °F | 50.0 °F | 3.98 in. |
| December | 23.3 °F | 39.8 °F | 4.78 in. |
| Annual | 39 °F | 58.3 °F | 49.93 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 6b : -5°F to 0°F |
| Plant Hardiness Zone - 2012 | Zone 6a : -10°F to -5°F |
| Current Drought Conditions | Severe Drought |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |