New Haven, Vermont has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 1.7 °C (low) to 13 °C (high). Annual precipitation averages 984.5 Millimeters. New Haven is located in USDA Plant Hardiness Zone 5a. 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 | -12.3 °C | -2.1 °C | 65.53 mm |
| February | -11.8 °C | -0.6 °C | 47.24 mm |
| March | -6.5 °C | 4.3 °C | 57.66 mm |
| April | 0.2 °C | 12.2 °C | 78.23 mm |
| May | 6.8 °C | 19.6 °C | 90.68 mm |
| June | 12 °C | 24.3 °C | 99.06 mm |
| July | 14.9 °C | 27.1 °C | 118.62 mm |
| August | 13.9 °C | 26.1 °C | 102.36 mm |
| September | 9.6 °C | 21.9 °C | 81.79 mm |
| October | 3.4 °C | 14.4 °C | 95.76 mm |
| November | -1.8 °C | 7.6 °C | 75.18 mm |
| December | -7.9 °C | 1.2 °C | 72.39 mm |
| Annual | 1.7 °C | 13 °C | 984.5 mm |
| Average First Frost Date | Oct. 1 - Oct. 10 |
| Average Last Frost Date | May 1 - May 10 |
| Average Days With Frost | 150-180 Days |
| Plant Hardiness Zone | Zone 5a : -28.9°C to -26.1°C |
| Plant Hardiness Zone - 2012 | Zone 5a : -28.9°C to -26.1°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |