Evanston, WY 82931 Frost Dates
82931, near Evanston, WY: the frost window
Typically, the last spring freeze lands around 06/12, roughly 288 days out. Fall's first freeze usually shows up around 09/12, roughly 90 days after the last spring frost.
The USDA Plant Hardiness Zone Map puts Evanston in Zone 5a (-20 to -15°F average annual minimum); frost dates are NOAA's 1991-2020 station normal, not this year's forecast.
Stretching the season past the first frost
Evanston's growing season runs out in roughly 2 weeks — a cold frame or greenhouse kit is the usual way to keep cool-weather crops going past the first frost.
The actual range around Evanston's last frost
06/12 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 05/26 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 07/02 and only about 1 year in 10 sees frost after that.
Evanston against the rest of the dataset
At roughly 90 frost-free days, Evanston places 39,911 of 40,283 ZIP codes in this dataset. Within WY, it ranks 145 of 192.
Learn more
Two guides worth reading on 82931: zone vs. frost date, on why Zone 5a and Evanston's frost date answer different questions, and the frost range, on how to read the range around Evanston's dates instead of trusting one.