Fortville, Indiana has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 5.8 °C (low) to 16.4 °C (high). Annual precipitation averages 1124.7 Millimeters. Fortville is located in USDA Plant Hardiness Zone 6a. The growing season typically runs from the last frost around Apr. 11 - Apr. 20 through the first frost around Oct. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -7.1 °C | 1.6 °C | 75.69 mm |
| February | -5.6 °C | 3.8 °C | 61.98 mm |
| March | -0.9 °C | 9.8 °C | 85.34 mm |
| April | 5.1 °C | 16.9 °C | 113.54 mm |
| May | 11.3 °C | 22.5 °C | 125.48 mm |
| June | 16.3 °C | 27.1 °C | 133.1 mm |
| July | 17.9 °C | 28.8 °C | 112.01 mm |
| August | 16.9 °C | 28.2 °C | 86.36 mm |
| September | 12.6 °C | 25.2 °C | 84.07 mm |
| October | 6.4 °C | 18.3 °C | 82.04 mm |
| November | 0.7 °C | 10.6 °C | 86.11 mm |
| December | -4.1 °C | 4.1 °C | 78.99 mm |
| Annual | 5.8 °C | 16.4 °C | 1124.71 mm |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | Apr. 11 - Apr. 20 |
| Average Days With Frost | 100-125 Days |
| Plant Hardiness Zone | Zone 6a : -23.3°C to -20.6°C |
| Plant Hardiness Zone - 2012 | Zone 6a : -23.3°C to -20.6°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |