Mansfield, Illinois has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 5.3 °C (low) to 16.6 °C (high). Annual precipitation averages 996.5 Millimeters. Mansfield 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. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -8.2 °C | 0.8 °C | 55.88 mm |
| February | -6.4 °C | 3.3 °C | 48.26 mm |
| March | -1.3 °C | 9.8 °C | 67.56 mm |
| April | 4.7 °C | 17.4 °C | 101.85 mm |
| May | 11.3 °C | 23.3 °C | 110.24 mm |
| June | 16.3 °C | 28 °C | 117.6 mm |
| July | 17.8 °C | 29.3 °C | 105.16 mm |
| August | 16.6 °C | 28.5 °C | 84.33 mm |
| September | 12.4 °C | 26 °C | 83.57 mm |
| October | 5.7 °C | 18.8 °C | 85.85 mm |
| November | -0.1 °C | 10.4 °C | 75.95 mm |
| December | -4.9 °C | 3.5 °C | 60.2 mm |
| Annual | 5.3 °C | 16.6 °C | 996.45 mm |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| 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 |