Vergennes, Vermont has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 2.4 °C (low) to 13.5 °C (high). Annual precipitation averages 936.2 Millimeters. Vergennes 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 | -11.6 °C | -1.6 °C | 61.72 mm |
| February | -11.1 °C | -0.3 °C | 45.21 mm |
| March | -5.7 °C | 4.7 °C | 55.37 mm |
| April | 0.9 °C | 12.7 °C | 74.93 mm |
| May | 7.5 °C | 20.1 °C | 85.09 mm |
| June | 12.8 °C | 24.8 °C | 96.77 mm |
| July | 15.7 °C | 27.8 °C | 107.44 mm |
| August | 14.8 °C | 26.8 °C | 95.25 mm |
| September | 10.3 °C | 22.6 °C | 79.5 mm |
| October | 4.1 °C | 14.9 °C | 93.22 mm |
| November | -1.1 °C | 8 °C | 71.37 mm |
| December | -7.3 °C | 1.6 °C | 70.36 mm |
| Annual | 2.4 °C | 13.5 °C | 936.23 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 |