West Simsbury, Connecticut has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 4.3 °C (low) to 15.8 °C (high). Annual precipitation averages 1318 Millimeters. West Simsbury 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 | 93.22 mm |
| February | -7.4 °C | 3.4 °C | 82.8 mm |
| March | -3.2 °C | 7.9 °C | 108.71 mm |
| April | 2.7 °C | 15.3 °C | 102.11 mm |
| May | 8.6 °C | 21.4 °C | 101.35 mm |
| June | 13.8 °C | 26.1 °C | 120.65 mm |
| July | 16.7 °C | 28.9 °C | 114.3 mm |
| August | 15.8 °C | 27.9 °C | 115.82 mm |
| September | 11.6 °C | 23.9 °C | 123.19 mm |
| October | 5.3 °C | 17.1 °C | 138.18 mm |
| November | -0.1 °C | 10.6 °C | 100.84 mm |
| December | -4.6 °C | 4.7 °C | 116.84 mm |
| Annual | 4.3 °C | 15.8 °C | 1318.01 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 | Dfa - Humid Continental Hot Summers With Year Around Precipitation |