Hartland, Connecticut has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 38.3 °F (low) to 59.3 °F (high). Annual precipitation averages 50.5 Inches. Hartland is located in USDA Plant Hardiness Zone 6a. The growing season typically runs from the last frost around May 1 - May 10 through the first frost around Oct. 1 - Oct. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 15.6 °F | 34.0 °F | 3.67 in. |
| February | 16.9 °F | 37.0 °F | 3.19 in. |
| March | 25.1 °F | 45.2 °F | 3.91 in. |
| April | 35.8 °F | 58.6 °F | 3.7 in. |
| May | 46.2 °F | 69.7 °F | 4.24 in. |
| June | 55.7 °F | 78.0 °F | 4.84 in. |
| July | 60.8 °F | 83.0 °F | 4.59 in. |
| August | 58.9 °F | 81.2 °F | 4.16 in. |
| September | 51.5 °F | 74.0 °F | 4.95 in. |
| October | 40.3 °F | 61.8 °F | 5.18 in. |
| November | 30.8 °F | 49.9 °F | 3.82 in. |
| December | 22.5 °F | 39.2 °F | 4.22 in. |
| Annual | 38.3 °F | 59.3 °F | 50.47 in. |
| Average First Frost Date | Oct. 1 - Oct. 10 |
| Average Last Frost Date | May 1 - May 10 |
| Average Days With Frost | 125-150 Days |
| Plant Hardiness Zone | Zone 6a : -10°F to -5°F |
| Plant Hardiness Zone - 2012 | Zone 5b : -15°F to -10°F |
| Current Drought Conditions | Moderate Drought |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |