Pine Haven, WY 82721 Frost Dates
82721, near Pine Haven, WY: the frost window
The last spring frost here typically falls around 05/23, about 268 days from today. Fall's first freeze usually shows up around 09/20, roughly 118 days after the last spring frost.
Zone 4b (-25 to -20°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 Pine Haven, not a forecast for this year.
Stretching the season past the first frost
Pine Haven's growing season runs out in roughly 3 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 Pine Haven's last frost
05/23 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 06/06 and only about 1 year in 10 sees frost after that.
Pine Haven against the rest of the dataset
Pine Haven's growing season runs about 118 days, ranking 39,221 of 40,283 US ZIP codes measured here, longest to shortest. Within WY, it ranks 108 of 192.
Learn more
Two guides worth reading on 82721: zone vs. frost date, on why Zone 4b and Pine Haven's frost date answer different questions, and the frost range, on how to read the range around Pine Haven's dates instead of trusting one.