Rocky Hill, Connecticut has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 5.1 °C (low) to 15.9 °C (high). Annual precipitation averages 1263.4 Millimeters. Rocky Hill 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 | -7 °C | 2.3 °C | 95.76 mm |
| February | -6.3 °C | 3.8 °C | 82.55 mm |
| March | -2.1 °C | 8.2 °C | 111 mm |
| April | 3.6 °C | 15.2 °C | 106.43 mm |
| May | 9.2 °C | 21.2 °C | 94.74 mm |
| June | 14.4 °C | 25.9 °C | 121.16 mm |
| July | 17.4 °C | 28.9 °C | 105.41 mm |
| August | 16.6 °C | 27.9 °C | 102.62 mm |
| September | 12.4 °C | 23.9 °C | 110.24 mm |
| October | 6.1 °C | 17.2 °C | 125.48 mm |
| November | 0.7 °C | 10.9 °C | 96.52 mm |
| December | -3.7 °C | 5.3 °C | 111.51 mm |
| Annual | 5.1 °C | 15.9 °C | 1263.42 mm |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | Apr. 11 - Apr. 20 |
| Average Days With Frost | 100-125 Days |
| Plant Hardiness Zone | Zone 6b : -20.6°C to -17.8°C |
| Plant Hardiness Zone - 2012 | Zone 6b : -20.6°C to -17.8°C |
| Current Drought Conditions | Moderate Drought |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |