Lombard, Illinois has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 40.9 °F (low) to 59.7 °F (high). Annual precipitation averages 39.6 Inches. Lombard is located in USDA Plant Hardiness Zone 6a. The growing season typically runs from the last frost around Apr. 21 - Apr. 30 through the first frost around Oct. 21 - Oct. 31.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 16.2 °F | 31.4 °F | 2.15 in. |
| February | 18.8 °F | 35.3 °F | 2.14 in. |
| March | 28.2 °F | 46.7 °F | 2.32 in. |
| April | 38.5 °F | 59.4 °F | 3.89 in. |
| May | 49.4 °F | 70.6 °F | 4.8 in. |
| June | 59.5 °F | 80.5 °F | 4.53 in. |
| July | 64.5 °F | 84.7 °F | 3.76 in. |
| August | 63.0 °F | 82.7 °F | 4.21 in. |
| September | 55.2 °F | 76.2 °F | 3.39 in. |
| October | 43.0 °F | 63.0 °F | 3.49 in. |
| November | 31.8 °F | 48.6 °F | 2.59 in. |
| December | 22.1 °F | 36.7 °F | 2.28 in. |
| Annual | 40.9 °F | 59.7 °F | 39.55 in. |
| Average First Frost Date | Oct. 21 - Oct. 31 |
| Average Last Frost Date | Apr. 21 - Apr. 30 |
| 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 |