Smithville, Ohio has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 40.6 °F (low) to 59.6 °F (high). Annual precipitation averages 40.1 Inches. Smithville is located in USDA Plant Hardiness Zone 6a. 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 | 18.7 °F | 33.8 °F | 2.74 in. |
| February | 20.0 °F | 36.8 °F | 2.09 in. |
| March | 27.9 °F | 46.4 °F | 2.99 in. |
| April | 38.6 °F | 59.9 °F | 3.81 in. |
| May | 49.2 °F | 70.3 °F | 4.06 in. |
| June | 58.5 °F | 78.9 °F | 4.36 in. |
| July | 61.9 °F | 82.1 °F | 3.95 in. |
| August | 60.1 °F | 80.7 °F | 3.72 in. |
| September | 52.9 °F | 74.9 °F | 3.43 in. |
| October | 42.0 °F | 62.5 °F | 3.28 in. |
| November | 32.6 °F | 49.9 °F | 2.89 in. |
| December | 24.7 °F | 38.6 °F | 2.76 in. |
| Annual | 40.6 °F | 59.6 °F | 40.08 in. |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | May 1 - May 10 |
| Average Days With Frost | 125-150 Days |
| Plant Hardiness Zone | Zone 6a : -10°F to -5°F |
| Plant Hardiness Zone - 2012 | Zone 6a : -10°F to -5°F |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |