Barnesville, Ohio has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 5.1 °C (low) to 15.8 °C (high). Annual precipitation averages 1131.1 Millimeters. Barnesville is located in USDA Plant Hardiness Zone 6b. The growing season typically runs from the last frost around Apr. 21 - Apr. 30 through the first frost around Oct. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -6.8 °C | 2 °C | 87.88 mm |
| February | -5.8 °C | 3.8 °C | 64.01 mm |
| March | -1.7 °C | 9.2 °C | 91.95 mm |
| April | 4 °C | 16.3 °C | 102.11 mm |
| May | 9.6 °C | 21.3 °C | 110.24 mm |
| June | 14.8 °C | 25.8 °C | 129.03 mm |
| July | 16.9 °C | 27.8 °C | 108.97 mm |
| August | 15.6 °C | 27.1 °C | 93.47 mm |
| September | 11.8 °C | 23.9 °C | 97.54 mm |
| October | 5.7 °C | 17.2 °C | 78.74 mm |
| November | 0.6 °C | 10.6 °C | 82.04 mm |
| December | -3.7 °C | 4.6 °C | 85.09 mm |
| Annual | 5.1 °C | 15.8 °C | 1131.07 mm |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | Apr. 21 - Apr. 30 |
| Average Days With Frost | 100-125 Days |
| Plant Hardiness Zone | Zone 6b : -20.6°C to -17.8°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 |