Jackson, WY 83001 Frost Dates
83001, near Jackson, WY: the frost window
Around 06/20 is the usual last spring frost, about 296 days away. Fall's first freeze usually shows up around 08/31, roughly 70 days after the last spring frost.
Jackson 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
Jackson's growing season runs out in roughly any day now — a cold frame or greenhouse kit is the usual way to keep cool-weather crops going past the first frost.
Why 06/20 isn't a guarantee
06/20 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 06/05 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 07/09 and only about 1 year in 10 sees frost after that.
Jackson against the rest of the dataset
About 70 days separate Jackson's last and first frost, putting it 40,120 of 40,283 ZIP codes nationally. Within WY, it ranks 168 of 192.
Learn more
Two guides worth reading on 83001: the frost range, on how to read the range around Jackson's dates instead of trusting one, and local microclimates, on what one yard in Jackson can differ from the 83001 normal.