Brattleboro, Vermont has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 2.3 °C (low) to 14.7 °C (high). Annual precipitation averages 1257.6 Millimeters. Brattleboro 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 | -10.9 °C | 0.1 °C | 90.68 mm |
| February | -10.3 °C | 2 °C | 80.77 mm |
| March | -5.2 °C | 6.6 °C | 97.03 mm |
| April | 0.7 °C | 14 °C | 98.81 mm |
| May | 6.9 °C | 20.8 °C | 100.08 mm |
| June | 12.3 °C | 25.6 °C | 116.33 mm |
| July | 15.1 °C | 28.4 °C | 103.89 mm |
| August | 14.1 °C | 27.6 °C | 110.49 mm |
| September | 9.7 °C | 23.5 °C | 115.82 mm |
| October | 3.4 °C | 16.1 °C | 134.37 mm |
| November | -1.7 °C | 9.2 °C | 99.06 mm |
| December | -6.9 °C | 2.9 °C | 110.24 mm |
| Annual | 2.3 °C | 14.7 °C | 1257.57 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 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 |