Fairfield, Vermont has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 1.7 °C (low) to 12.5 °C (high). Annual precipitation averages 1059.7 Millimeters. Fairfield is located in USDA Plant Hardiness Zone 5a. The growing season typically runs from the last frost around Apr. 21 - Apr. 30 through the first frost around Oct. 1 - Oct. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -13.5 °C | -3 °C | 65.02 mm |
| February | -12.6 °C | -1.4 °C | 55.63 mm |
| March | -6.9 °C | 3.7 °C | 69.85 mm |
| April | 0.3 °C | 11.7 °C | 84.33 mm |
| May | 7.2 °C | 19.4 °C | 93.22 mm |
| June | 12.4 °C | 23.9 °C | 110.74 mm |
| July | 15.3 °C | 26.4 °C | 109.73 mm |
| August | 14.2 °C | 25.8 °C | 106.93 mm |
| September | 10.1 °C | 21.6 °C | 100.33 mm |
| October | 4.1 °C | 14.2 °C | 103.12 mm |
| November | -1.6 °C | 7.1 °C | 80.26 mm |
| December | -8.3 °C | 0.6 °C | 80.52 mm |
| Annual | 1.7 °C | 12.5 °C | 1059.68 mm |
| Average First Frost Date | Oct. 1 - Oct. 10 |
| Average Last Frost Date | Apr. 21 - Apr. 30 |
| 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 |