Smyrna, South Carolina has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 9.7 °C (low) to 22.1 °C (high). Annual precipitation averages 1136.4 Millimeters. Smyrna is located in USDA Plant Hardiness Zone 8a. 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 | -0.9 °C | 11 °C | 97.79 mm |
| February | 0.6 °C | 13.3 °C | 83.57 mm |
| March | 4.2 °C | 17.6 °C | 109.22 mm |
| April | 8.9 °C | 22.6 °C | 96.27 mm |
| May | 13.9 °C | 26.4 °C | 88.9 mm |
| June | 18.6 °C | 30.1 °C | 101.09 mm |
| July | 20.5 °C | 32 °C | 92.2 mm |
| August | 19.9 °C | 31.1 °C | 108.97 mm |
| September | 16.6 °C | 28.2 °C | 92.71 mm |
| October | 9.6 °C | 22.8 °C | 78.99 mm |
| November | 3.6 °C | 17.1 °C | 85.34 mm |
| December | 0.6 °C | 12.4 °C | 101.35 mm |
| Annual | 9.7 °C | 22.1 °C | 1136.4 mm |
| Average First Frost Date | Oct. 21 - Oct. 31 |
| Average Last Frost Date | Apr. 11 - Apr. 20 |
| Average Days With Frost | 75-100 Days |
| Plant Hardiness Zone | Zone 8a : -12.2°C to -9.4°C |
| Plant Hardiness Zone - 2012 | Zone 7b : -15°C to -12.2°C |
| Current Drought Conditions | Moderate Drought |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |