JACKSON, Wyo. – A widespread fall freeze is setting in across western and southern Wyoming, with sub-freezing temperatures blanketing valleys and basins early Sunday and another hard freeze expected Monday morning. The cold will mark a major seasonal shift as fall conditions tighten their grip on the region.
According to the National Weather Service in Riverton, a Freeze Warning remains in effect until 10 a.m. Sunday for Jackson Hole, Star Valley, the Upper Wind River Basin, and South Lincoln County, including Jackson, Afton, Dubois, and Kemmerer. Overnight lows dropped into the mid-20s to upper 20s, especially in low-lying areas along rivers and creeks.
A second Freeze Warning has been issued for late Sunday night through 10 a.m. Monday for the Cody Foothills and Sweetwater County, including Cody, Green River, Rock Springs, and Wamsutter, where temperatures between 26 and 32 degrees are expected.
The cold could kill unprotected vegetation and damage outdoor plumbing. Residents should cover plants, disconnect hoses, and wrap pipes before temperatures plunge again tonight. Livestock and pet owners are advised to provide extra bedding and water access as the freeze deepens.
Forecasters say clear skies and calm winds will allow for strong radiational cooling both nights. Afternoon highs will stay mostly in the 50s through midweek before a modest warming trend begins late week.
Drivers may encounter frost on bridges and shaded roads early Monday, especially along U.S. 191, U.S. 89, and I-80 near Rock Springs.
