Glastonbury Center, Connecticut has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 5.2 °C (low) to 16 °C (high). Annual precipitation averages 1250.4 Millimeters. Glastonbury Center is located in USDA Plant Hardiness Zone 6b. The growing season typically runs from the last frost around Apr. 11 - Apr. 20 through the first frost around Oct. 21 - Oct. 31.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -7.1 °C | 2.3 °C | 93.47 mm |
| February | -6.3 °C | 3.8 °C | 81.79 mm |
| March | -1.9 °C | 8.3 °C | 109.47 mm |
| April | 3.8 °C | 15.2 °C | 104.39 mm |
| May | 9.4 °C | 21.2 °C | 91.19 mm |
| June | 14.7 °C | 25.9 °C | 117.6 mm |
| July | 17.7 °C | 28.9 °C | 105.16 mm |
| August | 16.8 °C | 28.1 °C | 105.92 mm |
| September | 12.6 °C | 24.1 °C | 114.81 mm |
| October | 6.2 °C | 17.4 °C | 122.17 mm |
| November | 0.7 °C | 11.1 °C | 93.73 mm |
| December | -3.7 °C | 5.4 °C | 110.74 mm |
| Annual | 5.2 °C | 16 °C | 1250.44 mm |
| Average First Frost Date | Oct. 21 - Oct. 31 |
| Average Last Frost Date | Apr. 11 - Apr. 20 |
| 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 | Dfa - Humid Continental Hot Summers With Year Around Precipitation |