Middlebury, 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 15.1 °C (high). Annual precipitation averages 1325.6 Millimeters. Middlebury is located in USDA Plant Hardiness Zone 6b. 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 | -7.9 °C | 1.7 °C | 95.5 mm |
| February | -7.1 °C | 3.2 °C | 81.53 mm |
| March | -3.1 °C | 7.6 °C | 111.25 mm |
| April | 2.8 °C | 14.5 °C | 104.65 mm |
| May | 8.4 °C | 20.4 °C | 104.39 mm |
| June | 13.5 °C | 25 °C | 118.62 mm |
| July | 16.4 °C | 27.7 °C | 119.38 mm |
| August | 15.7 °C | 26.7 °C | 117.6 mm |
| September | 11.8 °C | 22.8 °C | 118.36 mm |
| October | 5.4 °C | 16.4 °C | 135.13 mm |
| November | 0.3 °C | 10.3 °C | 102.87 mm |
| December | -4.6 °C | 4.4 °C | 116.33 mm |
| Annual | 4.3 °C | 15.1 °C | 1325.61 mm |
| 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 6b : -20.6°C to -17.8°C |
| Plant Hardiness Zone - 2012 | Zone 6a : -23.3°C to -20.6°C |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |