Barkhamsted, Connecticut has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 3.1 °C (low) to 15.1 °C (high). Annual precipitation averages 1301.8 Millimeters. Barkhamsted is located in USDA Plant Hardiness Zone 6a. The growing season typically runs from the last frost around Apr. 21 - Apr. 30 through the first frost around Oct. 1 - Oct. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -9.3 °C | 1.1 °C | 91.95 mm |
| February | -8.6 °C | 2.8 °C | 82.04 mm |
| March | -4.3 °C | 7.3 °C | 105.66 mm |
| April | 1.5 °C | 14.7 °C | 99.57 mm |
| May | 7.4 °C | 20.8 °C | 103.38 mm |
| June | 12.7 °C | 25.4 °C | 122.68 mm |
| July | 15.5 °C | 28.2 °C | 114.55 mm |
| August | 14.6 °C | 27.1 °C | 111.76 mm |
| September | 10.4 °C | 23.2 °C | 122.94 mm |
| October | 4.2 °C | 16.3 °C | 133.86 mm |
| November | -1.1 °C | 9.9 °C | 99.06 mm |
| December | -5.6 °C | 3.9 °C | 114.3 mm |
| Annual | 3.1 °C | 15.1 °C | 1301.75 mm |
| Average First Frost Date | Oct. 1 - Oct. 10 |
| Average Last Frost Date | Apr. 21 - Apr. 30 |
| Average Days With Frost | 125-150 Days |
| Plant Hardiness Zone | Zone 6a : -23.3°C to -20.6°C |
| Plant Hardiness Zone - 2012 | Zone 5b : -26.1°C to -23.3°C |
| Current Drought Conditions | Moderate Drought |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |