Calumet City, Illinois has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 6 °C (low) to 15.3 °C (high). Annual precipitation averages 1009.9 Millimeters. Calumet City 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. 21 - Oct. 31.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -7.4 °C | 0.5 °C | 57.4 mm |
| February | -5.9 °C | 2.4 °C | 53.85 mm |
| March | -1 °C | 8.1 °C | 60.2 mm |
| April | 4.6 °C | 14.8 °C | 93.22 mm |
| May | 10.4 °C | 20.8 °C | 107.7 mm |
| June | 15.9 °C | 26.3 °C | 117.09 mm |
| July | 18.9 °C | 28.6 °C | 109.73 mm |
| August | 18.2 °C | 27.7 °C | 104.39 mm |
| September | 14.1 °C | 24.4 °C | 83.06 mm |
| October | 7.5 °C | 17.4 °C | 92.2 mm |
| November | 1.3 °C | 9.8 °C | 71.88 mm |
| December | -4.2 °C | 3.3 °C | 59.18 mm |
| Annual | 6 °C | 15.3 °C | 1009.9 mm |
| 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 6a : -23.3°C to -20.6°C |
| Plant Hardiness Zone - 2012 | Zone 6a : -23.3°C to -20.6°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |