Bentley, Illinois has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 42.3 °F (low) to 62.5 °F (high). Annual precipitation averages 40.1 Inches. Bentley 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 | 16.7 °F | 33.7 °F | 1.74 in. |
| February | 20.4 °F | 38.5 °F | 1.98 in. |
| March | 30.5 °F | 50.6 °F | 2.54 in. |
| April | 41.3 °F | 63.6 °F | 4.06 in. |
| May | 52.8 °F | 73.7 °F | 5.33 in. |
| June | 62.5 °F | 82.9 °F | 4.88 in. |
| July | 66.0 °F | 86.5 °F | 4.14 in. |
| August | 63.7 °F | 84.8 °F | 3.94 in. |
| September | 55.1 °F | 79.0 °F | 3.71 in. |
| October | 43.5 °F | 66.1 °F | 3.2 in. |
| November | 32.2 °F | 51.4 °F | 2.63 in. |
| December | 22.4 °F | 38.7 °F | 1.96 in. |
| Annual | 42.3 °F | 62.5 °F | 40.11 in. |
| 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 : -10°F to -5°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 |