Swanton, Vermont has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 2.6 °C (low) to 12.7 °C (high). Annual precipitation averages 1023.6 Millimeters. Swanton 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 | -12.7 °C | -3.1 °C | 66.29 mm |
| February | -11.8 °C | -1.6 °C | 53.34 mm |
| March | -6.1 °C | 3.6 °C | 64.77 mm |
| April | 1.2 °C | 11.7 °C | 83.31 mm |
| May | 8.3 °C | 19.8 °C | 93.22 mm |
| June | 13.5 °C | 24.3 °C | 111.25 mm |
| July | 16.3 °C | 26.8 °C | 104.9 mm |
| August | 15.2 °C | 26.3 °C | 100.08 mm |
| September | 11 °C | 21.9 °C | 92.46 mm |
| October | 4.9 °C | 14.3 °C | 100.33 mm |
| November | -0.8 °C | 7.2 °C | 76.2 mm |
| December | -7.4 °C | 0.8 °C | 77.47 mm |
| Annual | 2.6 °C | 12.7 °C | 1023.62 mm |
| Average First Frost Date | Oct. 1 - Oct. 10 |
| Average Last Frost Date | May 1 - May 10 |
| Average Days With Frost | 125-150 Days |
| Plant Hardiness Zone | Zone 5a : -28.9°C to -26.1°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 |