Prospect, 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 59.1 °F (high). Annual precipitation averages 54.5 Inches. Prospect 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 | 17.3 °F | 34.6 °F | 4.08 in. |
| February | 18.9 °F | 37.3 °F | 3.53 in. |
| March | 26.4 °F | 45.2 °F | 5.13 in. |
| April | 36.7 °F | 58.3 °F | 4.37 in. |
| May | 46.8 °F | 69.2 °F | 4.52 in. |
| June | 56.0 °F | 77.4 °F | 4.6 in. |
| July | 61.2 °F | 82.2 °F | 4.4 in. |
| August | 59.9 °F | 80.4 °F | 4.28 in. |
| September | 52.8 °F | 73.4 °F | 4.76 in. |
| October | 41.8 °F | 61.7 °F | 5.63 in. |
| November | 32.3 °F | 50.2 °F | 4.4 in. |
| December | 23.3 °F | 39.4 °F | 4.75 in. |
| Annual | 39.5 °F | 59.1 °F | 54.45 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 6b : -5°F to 0°F |
| Current Drought Conditions | Moderate Drought |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |