Groton, Vermont has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Annual precipitation averages 1069.6 Millimeters. Groton is located in USDA Plant Hardiness Zone 4b. The growing season typically runs from the last frost around May 11 - May 20 through the first frost around Oct. 1 - Oct. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -14.4 °C | -3.1 °C | 69.09 mm |
| February | -14 °C | -1.1 °C | 58.67 mm |
| March | -8.5 °C | 4 °C | 70.61 mm |
| April | -1.3 °C | 11.6 °C | 84.07 mm |
| May | 5.4 °C | 18.8 °C | 101.09 mm |
| June | 10.4 °C | 23.5 °C | 101.85 mm |
| July | 13.4 °C | 26.4 °C | 108.71 mm |
| August | 12.2 °C | 25.6 °C | 106.68 mm |
| September | 8.1 °C | 21.4 °C | 95.25 mm |
| October | 1.9 °C | 13.8 °C | 110.49 mm |
| November | -3.4 °C | 6.7 °C | 77.47 mm |
| December | -9.6 °C | 0.2 °C | 85.6 mm |
| Annual | 0 °C | 12.3 °C | 1069.58 mm |
| Average First Frost Date | Oct. 1 - Oct. 10 |
| Average Last Frost Date | May 11 - May 20 |
| Average Days With Frost | 150-180 Days |
| Plant Hardiness Zone | Zone 4b : -31.7°C to -28.9°C |
| Plant Hardiness Zone - 2012 | Zone 4b : -31.7°C to -28.9°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |