Barnhill, Ohio has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 40.8 °F (low) to 61.5 °F (high). Annual precipitation averages 42.3 Inches. Barnhill 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 | 19.6 °F | 35.9 °F | 3.1 in. |
| February | 20.9 °F | 39.1 °F | 2.34 in. |
| March | 28.4 °F | 48.9 °F | 3.37 in. |
| April | 38.7 °F | 62.2 °F | 3.82 in. |
| May | 49.3 °F | 72.3 °F | 4.18 in. |
| June | 58.0 °F | 80.3 °F | 5.03 in. |
| July | 62.0 °F | 83.8 °F | 4.1 in. |
| August | 60.1 °F | 82.6 °F | 3.77 in. |
| September | 53.0 °F | 76.4 °F | 3.37 in. |
| October | 41.7 °F | 64.2 °F | 3.23 in. |
| November | 32.4 °F | 51.6 °F | 2.95 in. |
| December | 25.2 °F | 40.6 °F | 3.05 in. |
| Annual | 40.8 °F | 61.5 °F | 42.31 in. |
| 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 : -5°F to 0°F |
| Plant Hardiness Zone - 2012 | Zone 6a : -10°F to -5°F |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |