Willoughby Hills, Ohio has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 5.5 °C (low) to 14.6 °C (high). Annual precipitation averages 1135.4 Millimeters. Willoughby Hills 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 | 1.1 °C | 85.6 mm |
| February | -6.3 °C | 2.3 °C | 60.71 mm |
| March | -2.6 °C | 6.9 °C | 78.74 mm |
| April | 3.6 °C | 13.9 °C | 92.71 mm |
| May | 9.7 °C | 19.9 °C | 99.06 mm |
| June | 15.1 °C | 24.8 °C | 101.09 mm |
| July | 17.4 °C | 26.8 °C | 113.03 mm |
| August | 16.8 °C | 26.1 °C | 102.87 mm |
| September | 13.1 °C | 22.8 °C | 108.2 mm |
| October | 7.3 °C | 16.3 °C | 108.71 mm |
| November | 1.8 °C | 9.8 °C | 93.73 mm |
| December | -2.9 °C | 3.9 °C | 90.93 mm |
| Annual | 5.5 °C | 14.6 °C | 1135.38 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 |