Bison, SD 57649 Frost Dates
Bison, SD: when does the frost end?
Typically, the last spring freeze lands around 05/30, roughly 275 days out. Fall's first freeze usually shows up around 09/11, roughly 103 days after the last spring frost.
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.
Stretching the season past the first frost
With roughly 2 weeks until Bison's first fall frost, a row cover or cold frame is what stretches the last few weeks of harvest here.
The actual range around Bison's last frost
05/30 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 05/18 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 06/13 and only about 1 year in 10 sees frost after that.
Bison against the rest of the dataset
Bison's growing season runs about 103 days, ranking 39,629 of 40,283 US ZIP codes measured here, longest to shortest. Within SD, it ranks 377 of 378.
Learn more
Before leaning on 57649's figures: local microclimates explains what one yard in Bison can differ from the 57649 normal, while zone vs. frost date explains why Zone 4b and Bison's frost date answer different questions.