Lily Lake, Illinois has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 3.6 °C (low) to 14.5 °C (high). Annual precipitation averages 985.3 Millimeters. Lily Lake 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 | -10.4 °C | -1.6 °C | 48.01 mm |
| February | -8.6 °C | 0.8 °C | 46.99 mm |
| March | -3.2 °C | 7.4 °C | 59.18 mm |
| April | 2.4 °C | 14.7 °C | 93.98 mm |
| May | 8.9 °C | 21.1 °C | 127.25 mm |
| June | 14.4 °C | 26.4 °C | 112.52 mm |
| July | 16.7 °C | 28.2 °C | 99.57 mm |
| August | 15.7 °C | 27.1 °C | 100.33 mm |
| September | 11 °C | 23.7 °C | 91.69 mm |
| October | 4.7 °C | 16.5 °C | 85.09 mm |
| November | -1.2 °C | 8.3 °C | 65.02 mm |
| December | -7 °C | 1.4 °C | 55.63 mm |
| Annual | 3.6 °C | 14.5 °C | 985.26 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 |