Hanna, WY 82335 Frost Dates
82335, near Hanna, 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 09/07, roughly 83 days after the last spring frost.
Zone 5a (-20 to -15°F average annual minimum) comes from the USDA Plant Hardiness Zone Map; the frost dates above are the 1991-2020 normal at the nearest reporting NOAA station for Hanna, not a forecast for this year.
Stretching the season past the first frost
Hanna's growing season runs out in roughly 1 week — a cold frame or greenhouse kit is the usual way to keep cool-weather crops going past the first frost.
Why 06/12 isn't a guarantee
06/12 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 05/25 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 06/30 and only about 1 year in 10 sees frost after that.
Hanna against the rest of the dataset
About 83 days separate Hanna's last and first frost, putting it 40,027 of 40,283 ZIP codes nationally. Within WY, it ranks 157 of 192.
Learn more
Two guides worth reading on 82335: the frost range, on how to read the range around Hanna's dates instead of trusting one, and local microclimates, on what one yard in Hanna can differ from the 82335 normal.