Franklin, West Virginia has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 4.5 °C (low) to 17.8 °C (high). Annual precipitation averages 952.3 Millimeters. Franklin is located in USDA Plant Hardiness Zone 6b. The growing season typically runs from the last frost around May 1 - May 10 through the first frost around Oct. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -6.1 °C | 5.2 °C | 60.96 mm |
| February | -5.2 °C | 6.9 °C | 47.5 mm |
| March | -1.7 °C | 11.3 °C | 78.99 mm |
| April | 3.3 °C | 18.2 °C | 82.8 mm |
| May | 8.6 °C | 22.8 °C | 107.7 mm |
| June | 13.3 °C | 26.9 °C | 86.36 mm |
| July | 15.4 °C | 28.9 °C | 107.95 mm |
| August | 14.7 °C | 28.3 °C | 96.77 mm |
| September | 11 °C | 25.3 °C | 91.95 mm |
| October | 4.7 °C | 19.3 °C | 60.96 mm |
| November | -0.7 °C | 12.7 °C | 64.52 mm |
| December | -3.9 °C | 7.4 °C | 65.79 mm |
| Annual | 4.5 °C | 17.8 °C | 952.25 mm |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | May 1 - May 10 |
| Average Days With Frost | 100-125 Days |
| Plant Hardiness Zone | Zone 6b : -20.6°C to -17.8°C |
| Plant Hardiness Zone - 2012 | Zone 6b : -20.6°C to -17.8°C |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |