Last frost date in Riverton, Wyoming
May 12
Average last frost in spring. In an early year (1 in 10) it's over by May 1; in a late year (1 in 10) it comes after May 26.
September 24
Average first frost in fall. 1 year in 10 it comes by September 11.
Source: NOAA U.S. Climate Normals 1991–2020, station Riverton (USC00487760), 0.5 miles from Riverton, elevation 4,955 ft. NOAA National Centers for Environmental Information. These are long-term averages, not a forecast.
| Early year | Average | Late year | |
|---|---|---|---|
| Last frost in spring | May 1 | May 12 | May 26 |
| First frost in fall | Sept 11 | Sept 24 | Oct 7 |
Frost-free days in an average year: 132
| Chance in a year | Average last in spring | Average first in fall | |
|---|---|---|---|
| Light frost (36°F) | Every year | May 28 | Sept 14 |
| Frost (32°F) | Every year | May 12 | Sept 24 |
| Hard freeze (28°F) | Every year | May 1 | Oct 4 |
Nights at 32°F or colder in an average year: 193
What to plant now in Riverton
- Spring planting calendar for an average last frost around May 10 Riverton: May 12
- Fall planting calendar for an average first frost around September 20 Riverton: September 24
Planting dates: USDA Home and Garden Bulletin No. 9 (1967), “Suburban and Farm Vegetable Gardens,” tables 4 and 5. How we match the table.
Nearby in Wyoming
- Casper 105 mi · last frost May 10
- Rock Springs 108 mi · last frost May 24
- Cody 109 mi · last frost May 12
- Green River 118 mi · last frost May 24
- Jackson 124 mi · last frost June 20
Updated