Rocky Hill, New Jersey has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 6.3 °C (low) to 17.7 °C (high). Annual precipitation averages 1255.5 Millimeters. Rocky Hill is located in USDA Plant Hardiness Zone 7a. The growing season typically runs from the last frost around Apr. 11 - Apr. 20 through the first frost around Oct. 21 - Oct. 31.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -5.2 °C | 4.4 °C | 91.44 mm |
| February | -4.5 °C | 5.8 °C | 71.37 mm |
| March | -0.6 °C | 10.3 °C | 111.76 mm |
| April | 4.9 °C | 17.2 °C | 100.08 mm |
| May | 10.3 °C | 22.6 °C | 103.63 mm |
| June | 15.3 °C | 27.6 °C | 116.59 mm |
| July | 18.6 °C | 30.3 °C | 128.78 mm |
| August | 17.6 °C | 29.2 °C | 115.57 mm |
| September | 13.5 °C | 25.6 °C | 107.44 mm |
| October | 7.1 °C | 18.9 °C | 105.66 mm |
| November | 1.3 °C | 12.8 °C | 88.39 mm |
| December | -2.4 °C | 7.2 °C | 114.81 mm |
| Annual | 6.3 °C | 17.7 °C | 1255.52 mm |
| Average First Frost Date | Oct. 21 - Oct. 31 |
| Average Last Frost Date | Apr. 11 - Apr. 20 |
| Average Days With Frost | 100-125 Days |
| Plant Hardiness Zone | Zone 7a : -17.8°C to -15°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 |