Lee, Illinois has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 3.3 °C (low) to 14.4 °C (high). Annual precipitation averages 932.2 Millimeters. Lee 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 | -11 °C | -2.1 °C | 40.64 mm |
| February | -9 °C | 0.3 °C | 41.91 mm |
| March | -3.4 °C | 7.3 °C | 55.12 mm |
| April | 2.4 °C | 14.8 °C | 88.9 mm |
| May | 9.1 °C | 21.3 °C | 122.94 mm |
| June | 14.6 °C | 26.4 °C | 120.14 mm |
| July | 16.5 °C | 28 °C | 100.58 mm |
| August | 15.2 °C | 26.9 °C | 97.03 mm |
| September | 10.6 °C | 23.8 °C | 87.88 mm |
| October | 4.1 °C | 16.6 °C | 73.15 mm |
| November | -1.8 °C | 8.2 °C | 57.66 mm |
| December | -7.6 °C | 1 °C | 46.23 mm |
| Annual | 3.3 °C | 14.4 °C | 932.18 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 5a : -28.9°C to -26.1°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |