Colebrook, New Hampshire has a Subarctic With Cool Summers And Year Around Rainfall climate (Köppen classification: Dfc). Average annual temperatures range from -1 °C (low) to 11.4 °C (high). Annual precipitation averages 1048 Millimeters. Colebrook is located in USDA Plant Hardiness Zone 4a. The growing season typically runs from the last frost around May 21 - May 31 through the first frost around Sep.11 - Sep. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -15.9 °C | -4 °C | 66.29 mm |
| February | -15.5 °C | -2.4 °C | 50.55 mm |
| March | -9.6 °C | 2.6 °C | 63.25 mm |
| April | -2.1 °C | 10.4 °C | 76.2 mm |
| May | 4.4 °C | 18.4 °C | 104.9 mm |
| June | 9.6 °C | 22.9 °C | 115.32 mm |
| July | 12.4 °C | 25.5 °C | 109.47 mm |
| August | 11.4 °C | 24.8 °C | 101.6 mm |
| September | 7 °C | 20.6 °C | 87.12 mm |
| October | 1.4 °C | 13.2 °C | 109.73 mm |
| November | -4.2 °C | 5.6 °C | 79.5 mm |
| December | -10.7 °C | -0.8 °C | 84.07 mm |
| Annual | -1 °C | 11.4 °C | 1048 mm |
| Average First Frost Date | Sep.11 - Sep. 20 |
| Average Last Frost Date | May 21 - May 31 |
| Average Days With Frost | Over 180 Days |
| Plant Hardiness Zone | Zone 4a : -34.4°C to -31.7°C |
| Plant Hardiness Zone - 2012 | Zone 3b : -37.2°C to -34.4°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfc - Subarctic With Cool Summers And Year Around Rainfall |