Carman, Illinois has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 6 °C (low) to 16.4 °C (high). Annual precipitation averages 993.9 Millimeters. Carman 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 | -8.6 °C | 0.4 °C | 41.66 mm |
| February | -6.4 °C | 3 °C | 47.5 mm |
| March | -0.7 °C | 9.8 °C | 64.52 mm |
| April | 5.4 °C | 16.9 °C | 98.04 mm |
| May | 11.9 °C | 22.7 °C | 131.83 mm |
| June | 17.4 °C | 27.9 °C | 123.44 mm |
| July | 19.3 °C | 29.8 °C | 104.9 mm |
| August | 18.1 °C | 28.9 °C | 96.01 mm |
| September | 13.4 °C | 25.5 °C | 94.74 mm |
| October | 6.9 °C | 18.4 °C | 77.47 mm |
| November | 0.4 °C | 10.2 °C | 64.77 mm |
| December | -5.3 °C | 3.3 °C | 49.02 mm |
| Annual | 6 °C | 16.4 °C | 993.9 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 5b : -26.1°C to -23.3°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |