Riverton, Minnesota has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from -0.5 °C (low) to 10.8 °C (high). Annual precipitation averages 745 Millimeters. Riverton is located in USDA Plant Hardiness Zone 4a. The growing season typically runs from the last frost around May 1 - May 10 through the first frost around Sep. 21 - Sep. 30.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -17.8 °C | -7.2 °C | 20.32 mm |
| February | -16.3 °C | -4.1 °C | 21.08 mm |
| March | -8.8 °C | 3.1 °C | 36.83 mm |
| April | -0.8 °C | 11.1 °C | 58.42 mm |
| May | 6.6 °C | 18.5 °C | 88.9 mm |
| June | 12.4 °C | 23.9 °C | 111.25 mm |
| July | 14.6 °C | 26.6 °C | 113.54 mm |
| August | 13 °C | 25.3 °C | 89.66 mm |
| September | 8.3 °C | 20.6 °C | 74.17 mm |
| October | 1.6 °C | 12.4 °C | 71.12 mm |
| November | -5.5 °C | 3.4 °C | 35.05 mm |
| December | -12.8 °C | -4.1 °C | 24.64 mm |
| Annual | -0.5 °C | 10.8 °C | 744.98 mm |
| Average First Frost Date | Sep. 21 - Sep. 30 |
| Average Last Frost Date | May 1 - May 10 |
| Average Days With Frost | 150-180 Days |
| Plant Hardiness Zone | Zone 4a : -34.4°C to -31.7°C |
| Plant Hardiness Zone - 2012 | Zone 3b : -37.2°C to -34.4°C |
| Current Drought Conditions | Moderate Drought |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |