Coventry Lake, Connecticut has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 3.9 °C (low) to 15 °C (high). Annual precipitation averages 1259.1 Millimeters. Coventry Lake 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 | -8.1 °C | 1.8 °C | 90.68 mm |
| February | -7.4 °C | 3.2 °C | 78.23 mm |
| March | -3.2 °C | 7.5 °C | 110.24 mm |
| April | 2.3 °C | 14.2 °C | 112.01 mm |
| May | 7.8 °C | 20.1 °C | 91.69 mm |
| June | 12.9 °C | 24.7 °C | 110.74 mm |
| July | 16.1 °C | 27.4 °C | 101.35 mm |
| August | 15.1 °C | 26.6 °C | 113.28 mm |
| September | 11.2 °C | 22.9 °C | 116.08 mm |
| October | 4.9 °C | 16.4 °C | 123.7 mm |
| November | -0.2 °C | 10.4 °C | 99.06 mm |
| December | -4.4 °C | 4.9 °C | 112.01 mm |
| Annual | 3.9 °C | 15 °C | 1259.07 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 |