Ohio, Illinois has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 38.6 °F (low) to 58.5 °F (high). Annual precipitation averages 37.9 Inches. Ohio is located in USDA Plant Hardiness Zone 5b. 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 | 12.8 °F | 29.1 °F | 1.76 in. |
| February | 16.6 °F | 33.7 °F | 1.74 in. |
| March | 26.5 °F | 46.1 °F | 2.36 in. |
| April | 37.2 °F | 59.6 °F | 3.59 in. |
| May | 49.0 °F | 70.8 °F | 4.8 in. |
| June | 58.8 °F | 79.6 °F | 4.97 in. |
| July | 62.2 °F | 82.6 °F | 4.02 in. |
| August | 60.0 °F | 80.8 °F | 3.96 in. |
| September | 51.7 °F | 75.2 °F | 3.45 in. |
| October | 40.1 °F | 62.6 °F | 2.97 in. |
| November | 29.0 °F | 47.4 °F | 2.39 in. |
| December | 18.9 °F | 34.6 °F | 1.93 in. |
| Annual | 38.6 °F | 58.5 °F | 37.94 in. |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | Apr. 21 - Apr. 30 |
| Average Days With Frost | 125-150 Days |
| Plant Hardiness Zone | Zone 5b : -15°F to -10°F |
| Plant Hardiness Zone - 2012 | Zone 5b : -15°F to -10°F |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |