Kewanee, Illinois has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 4 °C (low) to 15.1 °C (high). Annual precipitation averages 986 Millimeters. Kewanee is located in USDA Plant Hardiness Zone 5b. 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 | -10.3 °C | -1.2 °C | 47.24 mm |
| February | -8.4 °C | 1.3 °C | 51.05 mm |
| March | -2.7 °C | 8.5 °C | 61.47 mm |
| April | 3.2 °C | 15.8 °C | 99.57 mm |
| May | 10 °C | 21.9 °C | 127.51 mm |
| June | 15.5 °C | 26.8 °C | 125.48 mm |
| July | 17.2 °C | 28.4 °C | 96.52 mm |
| August | 15.9 °C | 27.6 °C | 95.25 mm |
| September | 11.2 °C | 24.4 °C | 92.2 mm |
| October | 4.8 °C | 17.4 °C | 74.17 mm |
| November | -1.4 °C | 9 °C | 62.74 mm |
| December | -7.1 °C | 1.8 °C | 52.83 mm |
| Annual | 4 °C | 15.1 °C | 986.03 mm |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | Apr. 11 - Apr. 20 |
| Average Days With Frost | 125-150 Days |
| Plant Hardiness Zone | Zone 5b : -26.1°C to -23.3°C |
| Plant Hardiness Zone - 2012 | Zone 5b : -26.1°C to -23.3°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |