Bentley, Iowa has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 39.8 °F (low) to 60.7 °F (high). Annual precipitation averages 33.9 Inches. Bentley is located in USDA Plant Hardiness Zone 5b. The growing season typically runs from the last frost around Apr. 21 - Apr. 30 through the first frost around Oct. 1 - Oct. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 12.9 °F | 31.3 °F | 0.71 in. |
| February | 16.9 °F | 36.1 °F | 0.99 in. |
| March | 27.5 °F | 49.1 °F | 1.79 in. |
| April | 38.5 °F | 62.0 °F | 3.4 in. |
| May | 50.8 °F | 72.4 °F | 5.35 in. |
| June | 61.4 °F | 82.2 °F | 5.13 in. |
| July | 65.3 °F | 85.6 °F | 3.77 in. |
| August | 62.7 °F | 83.6 °F | 4.07 in. |
| September | 53.5 °F | 77.4 °F | 3.1 in. |
| October | 41.1 °F | 64.5 °F | 2.68 in. |
| November | 28.4 °F | 48.4 °F | 1.55 in. |
| December | 18.4 °F | 35.8 °F | 1.35 in. |
| Annual | 39.8 °F | 60.7 °F | 33.89 in. |
| Average First Frost Date | Oct. 1 - Oct. 10 |
| Average Last Frost Date | Apr. 21 - Apr. 30 |
| Average Days With Frost | 125-150 Days |
| Plant Hardiness Zone | Zone 5b : -15°F to -10°F |
| Plant Hardiness Zone - 2012 | Zone 5a : -20°F to -15°F |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |