Chicago, Illinois has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 44.9 °F (low) to 58.7 °F (high). Annual precipitation averages 40.4 Inches. Chicago is located in USDA Plant Hardiness Zone 6b. The growing season typically runs from the last frost around Apr. 11 - Apr. 20 through the first frost around Oct. 21 - Oct. 31.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 20.5 °F | 33.0 °F | 2.38 in. |
| February | 23.0 °F | 36.8 °F | 2.2 in. |
| March | 31.8 °F | 46.3 °F | 2.27 in. |
| April | 41.7 °F | 57.3 °F | 3.97 in. |
| May | 52.2 °F | 67.8 °F | 4.64 in. |
| June | 62.4 °F | 77.4 °F | 4.46 in. |
| July | 68.7 °F | 81.4 °F | 4.08 in. |
| August | 67.7 °F | 80.8 °F | 4.05 in. |
| September | 60.3 °F | 74.3 °F | 3.31 in. |
| October | 47.9 °F | 62.5 °F | 3.77 in. |
| November | 36.3 °F | 49.4 °F | 2.76 in. |
| December | 26.0 °F | 37.8 °F | 2.47 in. |
| Annual | 44.9 °F | 58.7 °F | 40.36 in. |
| Average First Frost Date | Oct. 21 - Oct. 31 |
| Average Last Frost Date | Apr. 11 - Apr. 20 |
| Average Days With Frost | 100-125 Days |
| Plant Hardiness Zone | Zone 6b : -5°F to 0°F |
| Plant Hardiness Zone - 2012 | Zone 6a : -10°F to -5°F |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |