Kirkwood, Illinois has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 4.8 °C (low) to 16 °C (high). Annual precipitation averages 969.8 Millimeters. Kirkwood 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 | -9.6 °C | -0.3 °C | 41.91 mm |
| February | -7.7 °C | 2.2 °C | 45.72 mm |
| March | -1.8 °C | 9.5 °C | 62.99 mm |
| April | 4.1 °C | 16.7 °C | 96.01 mm |
| May | 10.8 °C | 22.6 °C | 128.52 mm |
| June | 16.2 °C | 27.6 °C | 121.16 mm |
| July | 17.9 °C | 29.3 °C | 100.08 mm |
| August | 16.7 °C | 28.4 °C | 95 mm |
| September | 12.2 °C | 25.3 °C | 95.5 mm |
| October | 5.6 °C | 18.3 °C | 72.39 mm |
| November | -0.8 °C | 9.7 °C | 61.72 mm |
| December | -6.3 °C | 2.6 °C | 48.77 mm |
| Annual | 4.8 °C | 16 °C | 969.77 mm |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | Apr. 11 - Apr. 20 |
| Average Days With Frost | 100-125 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 |