Claremont, SD 57421 Frost Dates
57421, near Claremont, SD: the frost window
Around 05/06 is the usual last spring frost, about 251 days away. Fall's first freeze usually shows up around 10/04, roughly 150 days after the last spring frost.
Zone 4a (-30 to -25°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 Claremont, not a forecast for this year.
Stretching the season past the first frost
Claremont'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.
The actual range around Claremont's last frost
05/06 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 04/22 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 05/21 and only about 1 year in 10 sees frost after that.
Claremont against the rest of the dataset
At roughly 150 frost-free days, Claremont places 35,453 of 40,283 ZIP codes in this dataset. Within SD, it ranks 176 of 378.
Learn more
Two guides worth reading on 57421: local microclimates, on what one yard in Claremont can differ from the 57421 normal, and zone vs. frost date, on why Zone 4a and Claremont's frost date answer different questions.