Willoughby, Ohio has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 42.8 °F (low) to 58 °F (high). Annual precipitation averages 42.5 Inches. Willoughby is located in USDA Plant Hardiness Zone 7a. 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 | 21.1 °F | 34.4 °F | 3.15 in. |
| February | 21.6 °F | 35.9 °F | 2.24 in. |
| March | 28.1 °F | 43.5 °F | 2.86 in. |
| April | 39.2 °F | 56.6 °F | 3.47 in. |
| May | 50.4 °F | 67.5 °F | 3.73 in. |
| June | 60.0 °F | 76.4 °F | 3.75 in. |
| July | 64.3 °F | 80.0 °F | 4.24 in. |
| August | 63.2 °F | 78.7 °F | 3.93 in. |
| September | 56.5 °F | 72.9 °F | 4.16 in. |
| October | 46.1 °F | 61.3 °F | 4.18 in. |
| November | 36.1 °F | 49.8 °F | 3.45 in. |
| December | 27.4 °F | 39.4 °F | 3.35 in. |
| Annual | 42.8 °F | 58 °F | 42.51 in. |
| 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 7a : 0°F to 5°F |
| Plant Hardiness Zone - 2012 | Zone 6b : -5°F to 0°F |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |