Circleville, Ohio has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 6.2 °C (low) to 17.4 °C (high). Annual precipitation averages 1042.9 Millimeters. Circleville 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 | -5.6 °C | 3.2 °C | 74.42 mm |
| February | -4.7 °C | 5 °C | 64.77 mm |
| March | -0.4 °C | 10.6 °C | 86.36 mm |
| April | 5.3 °C | 17.9 °C | 101.85 mm |
| May | 11.4 °C | 23.3 °C | 112.52 mm |
| June | 16.3 °C | 27.9 °C | 116.08 mm |
| July | 18.1 °C | 29.3 °C | 101.6 mm |
| August | 16.8 °C | 28.9 °C | 86.11 mm |
| September | 12.8 °C | 25.8 °C | 75.95 mm |
| October | 6.6 °C | 19.1 °C | 74.68 mm |
| November | 0.9 °C | 11.7 °C | 73.15 mm |
| December | -2.7 °C | 5.8 °C | 75.44 mm |
| Annual | 6.2 °C | 17.4 °C | 1042.93 mm |
| 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 : -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 |