Carrollton, Illinois has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 6.2 °C (low) to 17.6 °C (high). Annual precipitation averages 1033.3 Millimeters. Carrollton is located in USDA Plant Hardiness Zone 6a. The growing season typically runs from the last frost around Apr. 1 - Apr. 10 through the first frost around Oct. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -7.1 °C | 2.3 °C | 57.91 mm |
| February | -5.2 °C | 5.3 °C | 54.1 mm |
| March | -0.2 °C | 11.4 °C | 77.72 mm |
| April | 5.7 °C | 18.1 °C | 111.76 mm |
| May | 12 °C | 23.6 °C | 125.22 mm |
| June | 17.2 °C | 28.3 °C | 114.81 mm |
| July | 18.9 °C | 30.1 °C | 97.03 mm |
| August | 17.7 °C | 29.5 °C | 87.12 mm |
| September | 12.9 °C | 26.3 °C | 83.82 mm |
| October | 6.6 °C | 19.6 °C | 79.76 mm |
| November | 0.7 °C | 11.6 °C | 82.55 mm |
| December | -4.3 °C | 5 °C | 61.47 mm |
| Annual | 6.2 °C | 17.6 °C | 1033.27 mm |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | Apr. 1 - Apr. 10 |
| 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 |