Bristol, Vermont has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 1.2 °C (low) to 12.7 °C (high). Annual precipitation averages 1089.2 Millimeters. Bristol 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 | -12.8 °C | -2.3 °C | 69.85 mm |
| February | -12.4 °C | -0.8 °C | 53.34 mm |
| March | -7.2 °C | 4.2 °C | 67.06 mm |
| April | -0.2 °C | 11.9 °C | 86.61 mm |
| May | 6.3 °C | 19.3 °C | 99.57 mm |
| June | 11.5 °C | 23.9 °C | 110.74 mm |
| July | 14.4 °C | 26.7 °C | 132.33 mm |
| August | 13.3 °C | 25.6 °C | 113.03 mm |
| September | 9.1 °C | 21.6 °C | 91.95 mm |
| October | 3 °C | 14.1 °C | 104.65 mm |
| November | -2.2 °C | 7.3 °C | 81.28 mm |
| December | -8.3 °C | 0.9 °C | 78.74 mm |
| Annual | 1.2 °C | 12.7 °C | 1089.15 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 |