North Stonington, Connecticut has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 4.6 °C (low) to 15.5 °C (high). Annual precipitation averages 1263.4 Millimeters. North Stonington 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 | -7.3 °C | 2.7 °C | 99.31 mm |
| February | -6.4 °C | 3.9 °C | 87.38 mm |
| March | -2.6 °C | 8.3 °C | 124.97 mm |
| April | 2.7 °C | 14.7 °C | 117.35 mm |
| May | 8.3 °C | 20.2 °C | 89.41 mm |
| June | 13.5 °C | 24.9 °C | 98.04 mm |
| July | 16.9 °C | 27.5 °C | 86.11 mm |
| August | 16 °C | 26.7 °C | 102.11 mm |
| September | 11.8 °C | 23.1 °C | 108.71 mm |
| October | 5.7 °C | 16.8 °C | 122.17 mm |
| November | 0.3 °C | 11.2 °C | 104.14 mm |
| December | -3.9 °C | 5.7 °C | 123.7 mm |
| Annual | 4.6 °C | 15.5 °C | 1263.4 mm |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | Apr. 21 - Apr. 30 |
| Average Days With Frost | 100-125 Days |
| Plant Hardiness Zone | Zone 6b : -20.6°C to -17.8°C |
| Plant Hardiness Zone - 2012 | Zone 6b : -20.6°C to -17.8°C |
| Current Drought Conditions | Moderate Drought |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |