Frost dates in Wyoming

Average last frost dates in Wyoming run from May 10 in Casper to June 20 in Jackson.

Average frost dates for 11 places in Wyoming
PlaceLast frostFirst frost
CasperMay 10Sept 29
CheyenneMay 14Oct 1
CodyMay 12Oct 1
EvanstonJune 12Sept 12
GilletteMay 15Oct 1
Green RiverMay 24Sept 22
JacksonJune 20Aug 31
LaramieJune 7Sept 4
RivertonMay 12Sept 24
Rock SpringsMay 24Sept 24
SheridanMay 21Sept 23

Source: NOAA U.S. Climate Normals 1991–2020, nearest station to each place. Places of 10,000+ people (US Census Bureau, 2024 estimates) within 50 miles of a station.

When to plant in Wyoming