Delaware, Ohio has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 5.7 °C (low) to 16.3 °C (high). Annual precipitation averages 1037.3 Millimeters. Delaware is located in USDA Plant Hardiness Zone 6b. 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 | -6.6 °C | 1.7 °C | 74.68 mm |
| February | -5.7 °C | 3.3 °C | 56.9 mm |
| March | -1 °C | 9.3 °C | 78.23 mm |
| April | 4.8 °C | 16.6 °C | 99.57 mm |
| May | 10.8 °C | 22.6 °C | 106.17 mm |
| June | 16.1 °C | 27.1 °C | 120.9 mm |
| July | 17.8 °C | 28.7 °C | 111.25 mm |
| August | 16.7 °C | 28 °C | 87.63 mm |
| September | 12.5 °C | 25 °C | 82.04 mm |
| October | 6.2 °C | 18.1 °C | 71.37 mm |
| November | 0.7 °C | 10.7 °C | 74.93 mm |
| December | -3.5 °C | 4.3 °C | 73.66 mm |
| Annual | 5.7 °C | 16.3 °C | 1037.33 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 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 |