Riverton, Iowa has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 40.4 °F (low) to 62.4 °F (high). Annual precipitation averages 34.2 Inches. Riverton 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. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 13.8 °F | 33.4 °F | 0.78 in. |
| February | 17.9 °F | 38.6 °F | 1.1 in. |
| March | 28.7 °F | 51.6 °F | 1.86 in. |
| April | 39.3 °F | 63.5 °F | 3.33 in. |
| May | 51.7 °F | 73.7 °F | 5.44 in. |
| June | 62.1 °F | 82.9 °F | 5.06 in. |
| July | 65.9 °F | 86.4 °F | 4.3 in. |
| August | 63.0 °F | 84.8 °F | 3.57 in. |
| September | 53.6 °F | 78.7 °F | 3.09 in. |
| October | 41.3 °F | 66.6 °F | 2.72 in. |
| November | 28.8 °F | 50.6 °F | 1.67 in. |
| December | 19.0 °F | 38.0 °F | 1.25 in. |
| Annual | 40.4 °F | 62.4 °F | 34.17 in. |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| 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 |