Byron, WY 82412 Frost Dates
82412, near Byron, WY: the frost window
Typically, the last spring freeze lands around 05/09, roughly 254 days out. Fall's first freeze usually shows up around 09/29, roughly 142 days after the last spring frost.
Byron sits in USDA Zone 5a (-20 to -15°F average annual minimum). The dates above are NOAA's 1991-2020 normal at the nearest reporting station, a 30-year average, not a forecast.
Stretching the season past the first frost
Byron's growing season runs out in roughly 5 weeks — a cold frame or greenhouse kit is the usual way to keep cool-weather crops going past the first frost.
How much risk comes with planting early here
05/09 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 04/27 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 05/25 and only about 1 year in 10 sees frost after that.
Byron against the rest of the dataset
About 142 days separate Byron's last and first frost, putting it 36,788 of 40,283 ZIP codes nationally. Within WY, it ranks 21 of 192.
Learn more
Two guides worth reading on 82412: zone vs. frost date, on why Zone 5a and Byron's frost date answer different questions, and the frost range, on how to read the range around Byron's dates instead of trusting one.