Casstown, Ohio has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 5.8 °C (low) to 16.7 °C (high). Annual precipitation averages 1048.2 Millimeters. Casstown is located in USDA Plant Hardiness Zone 6a. The growing season typically runs from the last frost around Apr. 21 - Apr. 30 through the first frost around Oct. 21 - Oct. 31.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -6.7 °C | 2 °C | 76.45 mm |
| February | -5.5 °C | 4.1 °C | 58.67 mm |
| March | -0.9 °C | 9.8 °C | 81.53 mm |
| April | 5 °C | 17 °C | 105.66 mm |
| May | 11.2 °C | 22.7 °C | 116.33 mm |
| June | 16.1 °C | 27.4 °C | 112.78 mm |
| July | 17.8 °C | 29.2 °C | 110.49 mm |
| August | 16.7 °C | 28.6 °C | 78.74 mm |
| September | 12.6 °C | 25.4 °C | 80.26 mm |
| October | 6.3 °C | 18.5 °C | 71.63 mm |
| November | 0.6 °C | 10.8 °C | 78.23 mm |
| December | -3.7 °C | 4.5 °C | 77.47 mm |
| Annual | 5.8 °C | 16.7 °C | 1048.24 mm |
| Average First Frost Date | Oct. 21 - Oct. 31 |
| Average Last Frost Date | Apr. 21 - Apr. 30 |
| Average Days With Frost | 100-125 Days |
| Plant Hardiness Zone | Zone 6a : -23.3°C to -20.6°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 |