Middletown, Ohio has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 6.4 °C (low) to 18 °C (high). Annual precipitation averages 1048 Millimeters. Middletown 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. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -5.4 °C | 3.7 °C | 78.74 mm |
| February | -4.4 °C | 5.8 °C | 60.45 mm |
| March | -0.1 °C | 11.4 °C | 91.44 mm |
| April | 5.5 °C | 18.3 °C | 109.73 mm |
| May | 11.4 °C | 23.8 °C | 113.03 mm |
| June | 16.5 °C | 28.2 °C | 116.33 mm |
| July | 18.4 °C | 30.1 °C | 96.01 mm |
| August | 17.4 °C | 29.7 °C | 77.98 mm |
| September | 12.8 °C | 26.4 °C | 69.6 mm |
| October | 6.3 °C | 19.7 °C | 75.44 mm |
| November | 0.7 °C | 12.2 °C | 75.18 mm |
| December | -2.8 °C | 6.1 °C | 84.07 mm |
| Annual | 6.4 °C | 18 °C | 1048 mm |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| 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 |