Collinsville, Connecticut has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 39.5 °F (low) to 60.4 °F (high). Annual precipitation averages 52.8 Inches. Collinsville is located in USDA Plant Hardiness Zone 6b. The growing season typically runs from the last frost around Apr. 11 - Apr. 20 through the first frost around Oct. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 17.5 °F | 35.3 °F | 3.67 in. |
| February | 18.7 °F | 38.4 °F | 3.33 in. |
| March | 26.2 °F | 46.5 °F | 4.21 in. |
| April | 36.6 °F | 59.6 °F | 4.03 in. |
| May | 47.2 °F | 70.5 °F | 4.1 in. |
| June | 56.6 °F | 79.0 °F | 4.73 in. |
| July | 61.9 °F | 84.2 °F | 4.7 in. |
| August | 60.1 °F | 82.1 °F | 4.81 in. |
| September | 52.7 °F | 75.0 °F | 4.99 in. |
| October | 41.3 °F | 62.7 °F | 5.62 in. |
| November | 31.7 °F | 51.2 °F | 3.98 in. |
| December | 23.8 °F | 40.6 °F | 4.63 in. |
| Annual | 39.5 °F | 60.4 °F | 52.8 in. |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | Apr. 11 - Apr. 20 |
| 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 | Moderate Drought |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |