Benton, Iowa has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 40.1 °F (low) to 61.2 °F (high). Annual precipitation averages 37.9 Inches. Benton 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 | 13.5 °F | 32.4 °F | 0.83 in. |
| February | 17.8 °F | 37.5 °F | 1.28 in. |
| March | 28.5 °F | 50.1 °F | 2.21 in. |
| April | 39.1 °F | 62.3 °F | 3.74 in. |
| May | 50.9 °F | 72.1 °F | 5.52 in. |
| June | 60.9 °F | 81.3 °F | 5.31 in. |
| July | 65.0 °F | 85.7 °F | 4.53 in. |
| August | 62.6 °F | 84.1 °F | 4.32 in. |
| September | 53.5 °F | 77.1 °F | 3.69 in. |
| October | 41.1 °F | 64.9 °F | 3.03 in. |
| November | 29.3 °F | 49.7 °F | 2.07 in. |
| December | 19.0 °F | 37.3 °F | 1.39 in. |
| Annual | 40.1 °F | 61.2 °F | 37.92 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 5b : -15°F to -10°F |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |