Middlefield, Connecticut has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 40.8 °F (low) to 60.6 °F (high). Annual precipitation averages 52.2 Inches. Middlefield 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. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 19.4 °F | 36.6 °F | 3.83 in. |
| February | 20.6 °F | 39.2 °F | 3.33 in. |
| March | 28.0 °F | 46.9 °F | 4.51 in. |
| April | 37.9 °F | 59.2 °F | 4.26 in. |
| May | 47.8 °F | 69.9 °F | 3.93 in. |
| June | 57.3 °F | 78.5 °F | 5.01 in. |
| July | 62.7 °F | 84.0 °F | 4.21 in. |
| August | 61.3 °F | 82.1 °F | 4.25 in. |
| September | 53.9 °F | 74.9 °F | 4.6 in. |
| October | 42.5 °F | 62.8 °F | 5.49 in. |
| November | 33.0 °F | 51.8 °F | 4.1 in. |
| December | 25.2 °F | 41.8 °F | 4.64 in. |
| Annual | 40.8 °F | 60.6 °F | 52.16 in. |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | Apr. 11 - Apr. 20 |
| Average Days With Frost | 100-125 Days |
| Plant Hardiness Zone | Zone 6b : -5°F to 0°F |
| Plant Hardiness Zone - 2012 | Zone 6b : -5°F to 0°F |
| Current Drought Conditions | Moderate Drought |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |