Big Stone City, SD 57216 Frost Dates
Frost dates for Big Stone City, SD, ZIP 57216
Typically, the last spring freeze lands around 05/02, roughly 247 days out. The first fall frost typically arrives around 10/04, about 153 frost-free days later.
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 Big Stone City, not a forecast for this year.
What to do before the first frost
Zone 4b around Big Stone City has about 5 weeks left before the first fall frost — that's the usual window to get a cold frame up if you want to keep harvesting past it.
Why 05/02 isn't a guarantee
05/02 is the middle of 30 years of NOAA records, not a promise. Plant by 04/20 and you're betting against frost in roughly 9 years out of 10. 05/15 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Big Stone City compares
About 153 days separate Big Stone City's last and first frost, putting it 34,607 of 40,283 ZIP codes nationally. Within SD, it ranks 121 of 378.
Learn more
zone vs. frost date explains why Zone 4b and Big Stone City's frost date answer different questions, and the frost range explains how to read the range around Big Stone City's dates instead of trusting one.