Seabrook, Massachusetts has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 6.6 °C (low) to 14.8 °C (high). Annual precipitation averages 1261.6 Millimeters. Seabrook is located in USDA Plant Hardiness Zone 7a. The growing season typically runs from the last frost around Apr. 21 - Apr. 30 through the first frost around Oct. 21 - Oct. 31.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -4.5 °C | 3.9 °C | 107.19 mm |
| February | -4 °C | 4.4 °C | 94.49 mm |
| March | -0.8 °C | 7.3 °C | 131.57 mm |
| April | 4.1 °C | 12.1 °C | 111.76 mm |
| May | 9.2 °C | 17.3 °C | 89.41 mm |
| June | 14.4 °C | 22.4 °C | 94.49 mm |
| July | 18.2 °C | 26 °C | 75.95 mm |
| August | 17.9 °C | 25.7 °C | 93.47 mm |
| September | 14.3 °C | 22.5 °C | 103.12 mm |
| October | 8.5 °C | 16.9 °C | 121.67 mm |
| November | 3.4 °C | 11.8 °C | 106.17 mm |
| December | -1.1 °C | 7.1 °C | 132.33 mm |
| Annual | 6.6 °C | 14.8 °C | 1261.62 mm |
| Average First Frost Date | Oct. 21 - Oct. 31 |
| Average Last Frost Date | Apr. 21 - Apr. 30 |
| Average Days With Frost | 100-125 Days |
| Plant Hardiness Zone | Zone 7a : -17.8°C to -15°C |
| Plant Hardiness Zone - 2012 | Zone 7a : -17.8°C to -15°C |
| Current Drought Conditions | Severe Drought |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |