Newington, New Hampshire has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 3.4 °C (low) to 14.4 °C (high). Annual precipitation averages 1214.9 Millimeters. Newington 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. 1 - Oct. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -9 °C | 0.9 °C | 87.88 mm |
| February | -8.2 °C | 2.3 °C | 87.38 mm |
| March | -3.9 °C | 6.4 °C | 110.24 mm |
| April | 1.7 °C | 13.3 °C | 113.54 mm |
| May | 7.3 °C | 19.1 °C | 98.04 mm |
| June | 12.7 °C | 24.3 °C | 105.16 mm |
| July | 15.8 °C | 27.5 °C | 93.47 mm |
| August | 15 °C | 26.9 °C | 81.79 mm |
| September | 10.8 °C | 22.8 °C | 100.33 mm |
| October | 4.6 °C | 15.9 °C | 123.19 mm |
| November | -0.5 °C | 9.7 °C | 100.84 mm |
| December | -5.4 °C | 3.8 °C | 113.03 mm |
| Annual | 3.4 °C | 14.4 °C | 1214.89 mm |
| 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 6a : -23.3°C to -20.6°C |
| Plant Hardiness Zone - 2012 | Zone 6a : -23.3°C to -20.6°C |
| Current Drought Conditions | Moderate Drought |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |