Voluntown, Connecticut has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 4.9 °C (low) to 15.6 °C (high). Annual precipitation averages 1264.9 Millimeters. Voluntown is located in USDA Plant Hardiness Zone 6b. The growing season typically runs from the last frost around Apr. 21 - Apr. 30 through the first frost around Oct. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -6.9 °C | 2.8 °C | 99.06 mm |
| February | -6.1 °C | 4.2 °C | 86.36 mm |
| March | -2.3 °C | 8.3 °C | 122.94 mm |
| April | 3.1 °C | 14.7 °C | 116.33 mm |
| May | 8.7 °C | 20.4 °C | 86.36 mm |
| June | 13.9 °C | 25.1 °C | 95.76 mm |
| July | 17.2 °C | 27.9 °C | 88.14 mm |
| August | 16.3 °C | 26.9 °C | 103.38 mm |
| September | 12.2 °C | 23.1 °C | 113.03 mm |
| October | 6.1 °C | 16.9 °C | 124.46 mm |
| November | 0.7 °C | 11.2 °C | 104.39 mm |
| December | -3.6 °C | 5.7 °C | 124.71 mm |
| Annual | 4.9 °C | 15.6 °C | 1264.92 mm |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | Apr. 21 - Apr. 30 |
| Average Days With Frost | 125-150 Days |
| Plant Hardiness Zone | Zone 6b : -20.6°C to -17.8°C |
| Plant Hardiness Zone - 2012 | Zone 6a : -23.3°C to -20.6°C |
| Current Drought Conditions | Moderate Drought |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |