Piedmont, SD 57769 Frost Dates
57769, near Piedmont, SD: the frost window
Typically, the last spring freeze lands around 05/10, roughly 255 days out. Fall's first freeze usually shows up around 10/05, roughly 147 days after the last spring frost.
Piedmont 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
Piedmont'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.
Why 05/10 isn't a guarantee
05/10 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.
Piedmont against the rest of the dataset
At roughly 147 frost-free days, Piedmont places 35,938 of 40,283 ZIP codes in this dataset. Within SD, it ranks 212 of 378.
Learn more
Two guides worth reading on 57769: zone vs. frost date, on why Zone 5a and Piedmont's frost date answer different questions, and the frost range, on how to read the range around Piedmont's dates instead of trusting one.