Rockville, South Carolina has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 14.9 °C (low) to 23.9 °C (high). Annual precipitation averages 1318.8 Millimeters. Rockville is located in USDA Plant Hardiness Zone 9a. The growing season typically runs from the last frost around Feb. 21 - Feb. 29 through the first frost around Dec. 1 - Dec. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 5.2 °C | 15 °C | 86.61 mm |
| February | 6.2 °C | 16.3 °C | 82.8 mm |
| March | 9.6 °C | 19.7 °C | 89.92 mm |
| April | 14 °C | 23.6 °C | 81.28 mm |
| May | 18.8 °C | 27.4 °C | 78.23 mm |
| June | 22.6 °C | 30.4 °C | 143.51 mm |
| July | 24.2 °C | 32.1 °C | 153.42 mm |
| August | 23.7 °C | 31.3 °C | 184.4 mm |
| September | 21.6 °C | 29.1 °C | 134.62 mm |
| October | 15.8 °C | 25.1 °C | 116.59 mm |
| November | 9.9 °C | 20.2 °C | 71.63 mm |
| December | 6.7 °C | 16.4 °C | 95.76 mm |
| Annual | 14.9 °C | 23.9 °C | 1318.77 mm |
| Average First Frost Date | Dec. 1 - Dec. 10 |
| Average Last Frost Date | Feb. 21 - Feb. 29 |
| Average Days With Frost | 10-20 Days |
| Plant Hardiness Zone | Zone 9a : -6.7°C to -3.9°C |
| Plant Hardiness Zone - 2012 | Zone 8b : -9.4°C to -6.7°C |
| Current Drought Conditions | Extreme Drought |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |