Middlebury, Vermont has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 1.8 °C (low) to 13.4 °C (high). Annual precipitation averages 985.8 Millimeters. Middlebury is located in USDA Plant Hardiness Zone 5a. The growing season typically runs from the last frost around May 1 - May 10 through the first frost around Sep. 21 - Sep. 30.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -12.1 °C | -1.8 °C | 61.72 mm |
| February | -11.6 °C | -0.3 °C | 48.26 mm |
| March | -6.3 °C | 4.8 °C | 58.17 mm |
| April | 0.3 °C | 12.9 °C | 79.76 mm |
| May | 6.8 °C | 20.1 °C | 90.68 mm |
| June | 12 °C | 24.9 °C | 104.9 mm |
| July | 14.8 °C | 27.6 °C | 107.19 mm |
| August | 13.9 °C | 26.6 °C | 97.28 mm |
| September | 9.7 °C | 22.5 °C | 85.34 mm |
| October | 3.4 °C | 14.8 °C | 101.6 mm |
| November | -1.6 °C | 7.8 °C | 73.66 mm |
| December | -7.7 °C | 1.4 °C | 77.22 mm |
| Annual | 1.8 °C | 13.4 °C | 985.78 mm |
| Average First Frost Date | Sep. 21 - Sep. 30 |
| Average Last Frost Date | May 1 - May 10 |
| Average Days With Frost | 150-180 Days |
| Plant Hardiness Zone | Zone 5a : -28.9°C to -26.1°C |
| Plant Hardiness Zone - 2012 | Zone 5a : -28.9°C to -26.1°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |