Bradley, Illinois has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 4.8 °C (low) to 15.9 °C (high). Annual precipitation averages 994.9 Millimeters. Bradley is located in USDA Plant Hardiness Zone 5b. 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 | -8.8 °C | 0 °C | 55.63 mm |
| February | -7.1 °C | 2.4 °C | 48.01 mm |
| March | -1.9 °C | 8.9 °C | 60.45 mm |
| April | 3.8 °C | 16.2 °C | 95.25 mm |
| May | 10.1 °C | 22.3 °C | 114.81 mm |
| June | 15.6 °C | 27.5 °C | 120.9 mm |
| July | 17.7 °C | 29.2 °C | 114.55 mm |
| August | 16.6 °C | 28.3 °C | 97.28 mm |
| September | 12.1 °C | 25.3 °C | 80.77 mm |
| October | 5.7 °C | 18.2 °C | 84.58 mm |
| November | -0.2 °C | 9.8 °C | 67.31 mm |
| December | -5.6 °C | 2.9 °C | 55.37 mm |
| Annual | 4.8 °C | 15.9 °C | 994.91 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 5b : -26.1°C to -23.3°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 |