Kewanee, Illinois has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 39.2 °F (low) to 59.3 °F (high). Annual precipitation averages 38.8 Inches. 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 | 13.4 °F | 29.8 °F | 1.86 in. |
| February | 16.8 °F | 34.4 °F | 2.01 in. |
| March | 27.1 °F | 47.3 °F | 2.42 in. |
| April | 37.8 °F | 60.4 °F | 3.92 in. |
| May | 50.0 °F | 71.5 °F | 5.02 in. |
| June | 59.9 °F | 80.3 °F | 4.94 in. |
| July | 63.0 °F | 83.2 °F | 3.8 in. |
| August | 60.7 °F | 81.7 °F | 3.75 in. |
| September | 52.2 °F | 76.0 °F | 3.63 in. |
| October | 40.7 °F | 63.3 °F | 2.92 in. |
| November | 29.4 °F | 48.2 °F | 2.47 in. |
| December | 19.3 °F | 35.3 °F | 2.08 in. |
| Annual | 39.2 °F | 59.3 °F | 38.82 in. |
| 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 : -15°F to -10°F |
| Plant Hardiness Zone - 2012 | Zone 5b : -15°F to -10°F |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |