Bristol, Connecticut has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 40 °F (low) to 60.8 °F (high). Annual precipitation averages 52.4 Inches. Bristol is located in USDA Plant Hardiness Zone 6b. The growing season typically runs from the last frost around Apr. 21 - Apr. 30 through the first frost around Oct. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 18.2 °F | 36.2 °F | 3.69 in. |
| February | 19.4 °F | 39.0 °F | 3.37 in. |
| March | 26.8 °F | 46.9 °F | 4.64 in. |
| April | 37.2 °F | 59.7 °F | 4.1 in. |
| May | 47.5 °F | 70.7 °F | 4.05 in. |
| June | 56.8 °F | 79.2 °F | 4.57 in. |
| July | 62.2 °F | 84.4 °F | 4.5 in. |
| August | 60.5 °F | 82.5 °F | 4.43 in. |
| September | 53.2 °F | 75.3 °F | 4.84 in. |
| October | 41.8 °F | 63.2 °F | 5.49 in. |
| November | 32.2 °F | 51.6 °F | 4.06 in. |
| December | 24.4 °F | 41.3 °F | 4.68 in. |
| Annual | 40 °F | 60.8 °F | 52.42 in. |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | Apr. 21 - Apr. 30 |
| Average Days With Frost | 125-150 Days |
| Plant Hardiness Zone | Zone 6b : -5°F to 0°F |
| Plant Hardiness Zone - 2012 | Zone 6a : -10°F to -5°F |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |