Terryville, Connecticut has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 38.6 °F (low) to 60.2 °F (high). Annual precipitation averages 53.5 Inches. Terryville is located in USDA Plant Hardiness Zone 6a. The growing season typically runs from the last frost around May 1 - May 10 through the first frost around Oct. 1 - Oct. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 16.9 °F | 35.5 °F | 3.82 in. |
| February | 18.2 °F | 38.4 °F | 3.33 in. |
| March | 25.4 °F | 46.3 °F | 4.67 in. |
| April | 35.7 °F | 59.5 °F | 4.15 in. |
| May | 46.0 °F | 70.4 °F | 4.23 in. |
| June | 55.3 °F | 78.8 °F | 4.64 in. |
| July | 60.6 °F | 83.6 °F | 4.76 in. |
| August | 59.1 °F | 81.7 °F | 4.65 in. |
| September | 51.8 °F | 74.4 °F | 4.79 in. |
| October | 40.4 °F | 62.5 °F | 5.62 in. |
| November | 30.9 °F | 50.9 °F | 4.16 in. |
| December | 23.1 °F | 40.3 °F | 4.72 in. |
| Annual | 38.6 °F | 60.2 °F | 53.54 in. |
| Average First Frost Date | Oct. 1 - Oct. 10 |
| Average Last Frost Date | May 1 - May 10 |
| Average Days With Frost | 125-150 Days |
| Plant Hardiness Zone | Zone 6a : -10°F to -5°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 |