Warrenville, Illinois has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 40 °F (low) to 59.8 °F (high). Annual precipitation averages 39.3 Inches. 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 | 15.3 °F | 31.1 °F | 2.05 in. |
| February | 18.0 °F | 35.1 °F | 2.0 in. |
| March | 27.6 °F | 46.9 °F | 2.37 in. |
| April | 38.0 °F | 59.9 °F | 3.9 in. |
| May | 49.0 °F | 71.1 °F | 4.91 in. |
| June | 59.0 °F | 80.8 °F | 4.53 in. |
| July | 63.6 °F | 84.5 °F | 3.87 in. |
| August | 61.8 °F | 82.7 °F | 4.05 in. |
| September | 54.0 °F | 76.5 °F | 3.3 in. |
| October | 41.8 °F | 63.4 °F | 3.56 in. |
| November | 30.9 °F | 48.6 °F | 2.58 in. |
| December | 21.2 °F | 36.4 °F | 2.22 in. |
| Annual | 40 °F | 59.8 °F | 39.34 in. |
| 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 : -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 |