Lee, Illinois has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 37.9 °F (low) to 57.9 °F (high). Annual precipitation averages 36.7 Inches. 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 | 12.2 °F | 28.2 °F | 1.6 in. |
| February | 15.8 °F | 32.6 °F | 1.65 in. |
| March | 25.9 °F | 45.1 °F | 2.17 in. |
| April | 36.3 °F | 58.7 °F | 3.5 in. |
| May | 48.3 °F | 70.3 °F | 4.84 in. |
| June | 58.2 °F | 79.5 °F | 4.73 in. |
| July | 61.7 °F | 82.4 °F | 3.96 in. |
| August | 59.3 °F | 80.4 °F | 3.82 in. |
| September | 51.0 °F | 74.8 °F | 3.46 in. |
| October | 39.3 °F | 61.9 °F | 2.88 in. |
| November | 28.8 °F | 46.7 °F | 2.27 in. |
| December | 18.4 °F | 33.8 °F | 1.82 in. |
| Annual | 37.9 °F | 57.9 °F | 36.7 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 5a : -20°F to -15°F |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |