Harpers Ferry, West Virginia has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 6.3 °C (low) to 18.5 °C (high). Annual precipitation averages 1061 Millimeters. Harpers Ferry 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 | -4.8 °C | 5.4 °C | 77.98 mm |
| February | -4 °C | 7.3 °C | 60.96 mm |
| March | -0.3 °C | 12 °C | 88.65 mm |
| April | 5.3 °C | 18.7 °C | 84.33 mm |
| May | 10.8 °C | 23.6 °C | 107.95 mm |
| June | 15.6 °C | 28.2 °C | 98.3 mm |
| July | 18 °C | 30.7 °C | 101.09 mm |
| August | 16.9 °C | 29.7 °C | 82.3 mm |
| September | 13.2 °C | 26 °C | 111.51 mm |
| October | 6.6 °C | 19.8 °C | 85.09 mm |
| November | 1.2 °C | 13.4 °C | 78.49 mm |
| December | -2.7 °C | 7.6 °C | 84.33 mm |
| Annual | 6.3 °C | 18.5 °C | 1060.98 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 | Moderate Drought |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |