Plaistow, New Hampshire has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 3.7 °C (low) to 15.2 °C (high). Annual precipitation averages 1217.4 Millimeters. Plaistow 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. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -8.9 °C | 1.6 °C | 88.9 mm |
| February | -7.9 °C | 3.1 °C | 87.38 mm |
| March | -3.7 °C | 7.3 °C | 115.06 mm |
| April | 2 °C | 14.3 °C | 105.66 mm |
| May | 7.7 °C | 20.1 °C | 97.54 mm |
| June | 13 °C | 25.1 °C | 107.7 mm |
| July | 16.3 °C | 28.3 °C | 90.68 mm |
| August | 15.3 °C | 27.4 °C | 89.41 mm |
| September | 11.1 °C | 23.4 °C | 97.54 mm |
| October | 4.6 °C | 16.6 °C | 124.97 mm |
| November | -0.4 °C | 10.4 °C | 97.28 mm |
| December | -5.3 °C | 4.6 °C | 115.32 mm |
| Annual | 3.7 °C | 15.2 °C | 1217.44 mm |
| 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 6a : -23.3°C to -20.6°C |
| Plant Hardiness Zone - 2012 | Zone 6a : -23.3°C to -20.6°C |
| Current Drought Conditions | Severe Drought |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |