Bradley, Illinois has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 40.7 °F (low) to 60.6 °F (high). Annual precipitation averages 39.2 Inches. 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 | 16.2 °F | 32.0 °F | 2.19 in. |
| February | 19.3 °F | 36.3 °F | 1.89 in. |
| March | 28.6 °F | 48.0 °F | 2.38 in. |
| April | 38.8 °F | 61.2 °F | 3.75 in. |
| May | 50.2 °F | 72.2 °F | 4.52 in. |
| June | 60.1 °F | 81.5 °F | 4.76 in. |
| July | 63.8 °F | 84.5 °F | 4.51 in. |
| August | 61.8 °F | 82.9 °F | 3.83 in. |
| September | 53.7 °F | 77.5 °F | 3.18 in. |
| October | 42.2 °F | 64.7 °F | 3.33 in. |
| November | 31.7 °F | 49.7 °F | 2.65 in. |
| December | 22.0 °F | 37.2 °F | 2.18 in. |
| Annual | 40.7 °F | 60.6 °F | 39.17 in. |
| 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 : -15°F to -10°F |
| Plant Hardiness Zone - 2012 | Zone 5b : -15°F to -10°F |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |