Blenheim, South Carolina has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 10.8 °C (low) to 23.4 °C (high). Annual precipitation averages 1214.6 Millimeters. Blenheim is located in USDA Plant Hardiness Zone 8b. The growing season typically runs from the last frost around Mar. 21 - Mar. 31 through the first frost around Nov. 1 - Nov. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 0.4 °C | 12.8 °C | 90.93 mm |
| February | 1.6 °C | 14.8 °C | 83.82 mm |
| March | 5 °C | 19 °C | 91.19 mm |
| April | 9.7 °C | 24 °C | 83.06 mm |
| May | 14.8 °C | 27.9 °C | 91.95 mm |
| June | 19.8 °C | 31.3 °C | 120.14 mm |
| July | 21.8 °C | 32.8 °C | 126.75 mm |
| August | 20.8 °C | 31.8 °C | 133.6 mm |
| September | 17.5 °C | 28.8 °C | 132.33 mm |
| October | 10.8 °C | 24.1 °C | 86.36 mm |
| November | 4.8 °C | 18.6 °C | 81.28 mm |
| December | 2 °C | 14.3 °C | 93.22 mm |
| Annual | 10.8 °C | 23.4 °C | 1214.63 mm |
| Average First Frost Date | Nov. 1 - Nov. 10 |
| Average Last Frost Date | Mar. 21 - Mar. 31 |
| Average Days With Frost | 50-75 Days |
| Plant Hardiness Zone | Zone 8b : -9.4°C to -6.7°C |
| Plant Hardiness Zone - 2012 | Zone 8a : -12.2°C to -9.4°C |
| Current Drought Conditions | Severe Drought |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |