Bison, SD 57644 Frost Dates
Frost dates for Bison, SD, ZIP 57644
The last spring frost here typically falls around 05/11, about 256 days from today. The first fall frost typically arrives around 09/30, about 140 frost-free days later.
The USDA Plant Hardiness Zone Map puts Bison in Zone 4b (-25 to -20°F average annual minimum); frost dates are NOAA's 1991-2020 station normal, not this year's forecast.
What to do before the first frost
Zone 4b around Bison 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.
The actual range around Bison's last frost
05/11 is the middle of 30 years of NOAA records, not a promise. Plant by 04/30 and you're betting against frost in roughly 9 years out of 10. 05/24 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Bison compares
At roughly 140 frost-free days, Bison places 37,154 of 40,283 ZIP codes in this dataset. Within SD, it ranks 309 of 378.
Learn more
the frost range explains how to read the range around Bison's dates instead of trusting one, and local microclimates explains what one yard in Bison can differ from the 57644 normal.