Warrenville, Illinois has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 4.5 °C (low) to 15.4 °C (high). Annual precipitation averages 999.2 Millimeters. Warrenville is located in USDA Plant Hardiness Zone 5b. The growing season typically runs from the last frost around Apr. 21 - Apr. 30 through the first frost around Oct. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -9.3 °C | -0.5 °C | 52.07 mm |
| February | -7.8 °C | 1.7 °C | 50.8 mm |
| March | -2.4 °C | 8.3 °C | 60.2 mm |
| April | 3.3 °C | 15.5 °C | 99.06 mm |
| May | 9.4 °C | 21.7 °C | 124.71 mm |
| June | 15 °C | 27.1 °C | 115.06 mm |
| July | 17.6 °C | 29.2 °C | 98.3 mm |
| August | 16.6 °C | 28.2 °C | 102.87 mm |
| September | 12.2 °C | 24.7 °C | 83.82 mm |
| October | 5.4 °C | 17.4 °C | 90.42 mm |
| November | -0.6 °C | 9.2 °C | 65.53 mm |
| December | -6 °C | 2.4 °C | 56.39 mm |
| Annual | 4.5 °C | 15.4 °C | 999.23 mm |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | Apr. 21 - Apr. 30 |
| 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 |