Unity, New Hampshire has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 2.2 °C (low) to 12.3 °C (high). Annual precipitation averages 1186.7 Millimeters. Unity is located in USDA Plant Hardiness Zone 6a. The growing season typically runs from the last frost around May 21 - May 31 through the first frost around Sep. 21 - Sep. 30.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -11 °C | -2.3 °C | 86.36 mm |
| February | -10.3 °C | -0.6 °C | 78.74 mm |
| March | -5.9 °C | 4 °C | 82.04 mm |
| April | 0.6 °C | 11.6 °C | 87.38 mm |
| May | 6.6 °C | 18.4 °C | 99.06 mm |
| June | 12.2 °C | 23.1 °C | 118.36 mm |
| July | 15.1 °C | 25.8 °C | 110.74 mm |
| August | 13.7 °C | 24.9 °C | 103.89 mm |
| September | 9.7 °C | 21.1 °C | 93.22 mm |
| October | 3.9 °C | 13.8 °C | 132.59 mm |
| November | -1.8 °C | 7.1 °C | 95.5 mm |
| December | -6.7 °C | 0.9 °C | 98.81 mm |
| Annual | 2.2 °C | 12.3 °C | 1186.69 mm |
| Average First Frost Date | Sep. 21 - Sep. 30 |
| Average Last Frost Date | May 21 - May 31 |
| Average Days With Frost | Over 180 Days |
| Plant Hardiness Zone | Zone 6a : -23.3°C to -20.6°C |
| Plant Hardiness Zone - 2012 | Zone 5b : -26.1°C to -23.3°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |