Cynthiana, Ohio has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 42.8 °F (low) to 62.9 °F (high). Annual precipitation averages 44.4 Inches. Cynthiana is located in USDA Plant Hardiness Zone 6b. The growing season typically runs from the last frost around Apr. 11 - Apr. 20 through the first frost around Oct. 21 - Oct. 31.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 21.4 °F | 38.0 °F | 3.2 in. |
| February | 23.7 °F | 41.6 °F | 3.1 in. |
| March | 31.2 °F | 51.3 °F | 4.05 in. |
| April | 41.1 °F | 63.9 °F | 4.37 in. |
| May | 52.0 °F | 72.9 °F | 4.7 in. |
| June | 60.7 °F | 81.2 °F | 4.54 in. |
| July | 63.6 °F | 84.0 °F | 4.35 in. |
| August | 61.5 °F | 83.2 °F | 3.46 in. |
| September | 54.4 °F | 77.9 °F | 3.21 in. |
| October | 43.4 °F | 66.1 °F | 3.06 in. |
| November | 33.4 °F | 52.8 °F | 2.98 in. |
| December | 26.7 °F | 42.1 °F | 3.4 in. |
| Annual | 42.8 °F | 62.9 °F | 44.42 in. |
| Average First Frost Date | Oct. 21 - Oct. 31 |
| Average Last Frost Date | Apr. 11 - Apr. 20 |
| 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 | Dfa - Humid Continental Hot Summers With Year Around Precipitation |