Mills, WY 82604 Frost Dates
Mills, WY: when does the frost end?
Around 05/26 is the usual last spring frost, about 271 days away. Fall's first freeze usually shows up around 09/22, roughly 117 days after the last spring frost.
The USDA Plant Hardiness Zone Map puts Mills 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
With roughly 4 weeks until Mills's first fall frost, a row cover or cold frame is what stretches the last few weeks of harvest here.
Why 05/26 isn't a guarantee
05/26 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 05/12 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 06/10 and only about 1 year in 10 sees frost after that.
Mills against the rest of the dataset
About 117 days separate Mills's last and first frost, putting it 39,245 of 40,283 ZIP codes nationally. Within WY, it ranks 112 of 192.
Learn more
Before leaning on 82604's figures: zone vs. frost date explains why Zone 5a and Mills's frost date answer different questions, while the frost range explains how to read the range around Mills's dates instead of trusting one.