Sinclair, WY 82615 Frost Dates
82615, near Sinclair, WY: the frost window
Typically, the last spring freeze lands around 06/01, roughly 277 days out. Fall's first freeze usually shows up around 09/15, roughly 105 days after the last spring frost.
Sinclair sits in USDA Zone 4b (-25 to -20°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
Sinclair'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.
Why 06/01 isn't a guarantee
06/01 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 05/17 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 06/17 and only about 1 year in 10 sees frost after that.
Sinclair against the rest of the dataset
At roughly 105 frost-free days, Sinclair places 39,604 of 40,283 ZIP codes in this dataset. Within WY, it ranks 135 of 192.
Learn more
Two guides worth reading on 82615: the frost range, on how to read the range around Sinclair's dates instead of trusting one, and local microclimates, on what one yard in Sinclair can differ from the 82615 normal.