Harpersville, Alabama has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 10.1 °C (low) to 24.1 °C (high). Annual precipitation averages 1426.5 Millimeters. Harpersville is located in USDA Plant Hardiness Zone 8a. The growing season typically runs from the last frost around Mar. 21 - Mar. 31 through the first frost around Oct. 21 - Oct. 31.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 0.3 °C | 13.1 °C | 132.59 mm |
| February | 1.9 °C | 15.7 °C | 139.19 mm |
| March | 5.2 °C | 20.1 °C | 137.16 mm |
| April | 9.1 °C | 24.6 °C | 125.48 mm |
| May | 14.1 °C | 28.3 °C | 112.78 mm |
| June | 18.6 °C | 31.6 °C | 123.44 mm |
| July | 20.4 °C | 33.2 °C | 116.59 mm |
| August | 19.9 °C | 32.8 °C | 106.17 mm |
| September | 16.7 °C | 30.5 °C | 101.09 mm |
| October | 9.9 °C | 25.2 °C | 84.33 mm |
| November | 4 °C | 19 °C | 113.79 mm |
| December | 1.6 °C | 14.5 °C | 133.86 mm |
| Annual | 10.1 °C | 24.1 °C | 1426.47 mm |
| Average First Frost Date | Oct. 21 - Oct. 31 |
| Average Last Frost Date | Mar. 21 - Mar. 31 |
| Average Days With Frost | 50-75 Days |
| Plant Hardiness Zone | Zone 8a : -12.2°C to -9.4°C |
| Plant Hardiness Zone - 2012 | Zone 8a : -12.2°C to -9.4°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |