Fairlee, Vermont has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 0.7 °C (low) to 13.6 °C (high). Annual precipitation averages 960.6 Millimeters. Fairlee 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 Oct. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -13.4 °C | -1.6 °C | 62.48 mm |
| February | -12.9 °C | 0.4 °C | 52.32 mm |
| March | -7.4 °C | 5.5 °C | 65.28 mm |
| April | -0.7 °C | 12.9 °C | 71.63 mm |
| May | 5.8 °C | 20.2 °C | 82.8 mm |
| June | 10.9 °C | 24.8 °C | 97.54 mm |
| July | 14.1 °C | 27.6 °C | 101.35 mm |
| August | 12.9 °C | 26.8 °C | 90.17 mm |
| September | 8.8 °C | 22.6 °C | 87.63 mm |
| October | 2.3 °C | 14.8 °C | 100.58 mm |
| November | -2.9 °C | 7.9 °C | 71.12 mm |
| December | -8.7 °C | 1.4 °C | 77.72 mm |
| Annual | 0.7 °C | 13.6 °C | 960.62 mm |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| 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 4b : -31.7°C to -28.9°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |