Rockhill, Pennsylvania has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 5.1 °C (low) to 17.1 °C (high). Annual precipitation averages 1040.4 Millimeters. Rockhill 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 | -6.2 °C | 3.3 °C | 70.87 mm |
| February | -5.5 °C | 5.2 °C | 60.2 mm |
| March | -1.6 °C | 10 °C | 87.88 mm |
| April | 3.8 °C | 17.3 °C | 91.69 mm |
| May | 9.4 °C | 22.7 °C | 105.16 mm |
| June | 14.4 °C | 27.4 °C | 99.06 mm |
| July | 16.9 °C | 29.9 °C | 90.68 mm |
| August | 16 °C | 28.9 °C | 89.41 mm |
| September | 11.9 °C | 25.1 °C | 99.31 mm |
| October | 5.6 °C | 18.4 °C | 88.39 mm |
| November | 0.4 °C | 11.8 °C | 75.95 mm |
| December | -3.6 °C | 5.5 °C | 81.79 mm |
| Annual | 5.1 °C | 17.1 °C | 1040.39 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 | Abnormally Dry |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |