Riverton, Wyoming has a Cold Semi-Arid Climate climate (Köppen classification: BSk). Average annual temperatures range from 30.5 °F (low) to 59.9 °F (high). Annual precipitation averages 9.5 Inches. Riverton is located in USDA Plant Hardiness Zone 4b. The growing season typically runs from the last frost around May 11 - May 20 through the first frost around Sep. 21 - Sep. 30.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 6.2 °F | 32.8 °F | 0.37 in. |
| February | 10.8 °F | 37.8 °F | 0.44 in. |
| March | 22.4 °F | 50.5 °F | 0.64 in. |
| April | 30.5 °F | 58.7 °F | 1.32 in. |
| May | 40.0 °F | 68.2 °F | 2.1 in. |
| June | 48.2 °F | 80.2 °F | 1.08 in. |
| July | 54.9 °F | 89.9 °F | 0.69 in. |
| August | 52.4 °F | 87.4 °F | 0.45 in. |
| September | 43.2 °F | 76.0 °F | 0.75 in. |
| October | 31.3 °F | 60.3 °F | 0.93 in. |
| November | 18.3 °F | 44.9 °F | 0.38 in. |
| December | 7.8 °F | 32.5 °F | 0.3 in. |
| Annual | 30.5 °F | 59.9 °F | 9.45 in. |
| Average First Frost Date | Sep. 21 - Sep. 30 |
| Average Last Frost Date | May 11 - May 20 |
| Average Days With Frost | 150-180 Days |
| Plant Hardiness Zone | Zone 4b : -25°F to -20°F |
| Plant Hardiness Zone - 2012 | Zone 4a : -30°F to -25°F |
| Current Drought Conditions | Extreme Drought |
| Köppen Climate Classification | BSk - Cold Semi-Arid Climate |