Riverton, Connecticut has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 3.5 °C (low) to 15.3 °C (high). Annual precipitation averages 1311.4 Millimeters. Riverton is located in USDA Plant Hardiness Zone 6a. The growing season typically runs from the last frost around May 1 - May 10 through the first frost around Oct. 1 - Oct. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -8.9 °C | 1.2 °C | 93.22 mm |
| February | -8.2 °C | 2.9 °C | 81.79 mm |
| March | -3.9 °C | 7.4 °C | 106.43 mm |
| April | 1.9 °C | 14.8 °C | 99.06 mm |
| May | 7.9 °C | 21.1 °C | 105.41 mm |
| June | 13.2 °C | 25.7 °C | 122.68 mm |
| July | 15.9 °C | 28.4 °C | 116.33 mm |
| August | 14.9 °C | 27.4 °C | 113.03 mm |
| September | 10.8 °C | 23.4 °C | 125.22 mm |
| October | 4.6 °C | 16.5 °C | 134.87 mm |
| November | -0.7 °C | 10.1 °C | 99.57 mm |
| December | -5.3 °C | 4.1 °C | 113.79 mm |
| Annual | 3.5 °C | 15.3 °C | 1311.4 mm |
| Average First Frost Date | Oct. 1 - Oct. 10 |
| Average Last Frost Date | May 1 - May 10 |
| Average Days With Frost | 125-150 Days |
| Plant Hardiness Zone | Zone 6a : -23.3°C to -20.6°C |
| Plant Hardiness Zone - 2012 | Zone 5b : -26.1°C to -23.3°C |
| Current Drought Conditions | Moderate Drought |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |