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Sweetwater County Planting Guide
The following information is provided as a general guide only and should not be taken as a guarantee of weather conditions or gardening success.
Growing Zones
USDA Growing Zones can be used a general indication of whether or not a plant will do well in an area. Some plants will grow as an annual in some zones and a perennial in others. Always check the zone hardiness of any plant you plan on growing here.
Rock Springs - Zone 5a
Green River - Zone 4b
Farson - Zone 4a
Reliance - Zone 5a
Granger - Zone 4a
Bairoil - Zone 5a
Wamsutter - Zone 4b
Superior - Zone 5a
McKinnon - Zone 5b
First and Last Frost Dates
The following date ranges represent the annual average risk of frost. It is still possible to have frost and freezing outside of these dates.
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City | First Frost Date | Last Frost Date | Average Frost Free Days |
|---|---|---|---|
Rock Springs | Sep. 18th | May 28th | 114 |
Green River | Sep. 4th | June 4th | 92 |
Farson | Aug. 28th | June 25th | 64 |
Reliance | Sep. 19th | May 28th | 114 |
Granger | Aug. 27th | June 26th | 62 |
Bairoil | Sep. 12 | June 6th | 98 |
Wamsutter | Sep. 10th | June 10th | 92 |
Superior | Aug. 28th | June 25th | 64 |
McKinnon | Sep. 16th | June 4th | 104 |
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