New Lenox, Illinois has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 41.2 °F (low) to 60.2 °F (high). Annual precipitation averages 40.1 Inches. New Lenox is located in USDA Plant Hardiness Zone 6a. The growing season typically runs from the last frost around Apr. 11 - Apr. 20 through the first frost around Oct. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 16.6 °F | 31.9 °F | 2.14 in. |
| February | 19.2 °F | 35.8 °F | 2.08 in. |
| March | 28.8 °F | 47.4 °F | 2.44 in. |
| April | 39.3 °F | 60.4 °F | 3.89 in. |
| May | 50.0 °F | 71.3 °F | 4.71 in. |
| June | 60.1 °F | 80.9 °F | 4.61 in. |
| July | 64.5 °F | 84.6 °F | 4.57 in. |
| August | 63.0 °F | 82.7 °F | 4.14 in. |
| September | 55.3 °F | 76.9 °F | 3.42 in. |
| October | 43.0 °F | 63.6 °F | 3.38 in. |
| November | 32.3 °F | 49.3 °F | 2.49 in. |
| December | 22.2 °F | 37.0 °F | 2.18 in. |
| Annual | 41.2 °F | 60.2 °F | 40.05 in. |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | Apr. 11 - Apr. 20 |
| Average Days With Frost | 100-125 Days |
| Plant Hardiness Zone | Zone 6a : -10°F to -5°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 |