Eagle Butte, SD 57630 Frost Dates
57630, near Eagle Butte, 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 09/30, roughly 141 days after the last spring frost.
The USDA Plant Hardiness Zone Map puts Eagle Butte 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
Eagle Butte'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 Eagle Butte's last frost
05/10 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 04/29 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 05/23 and only about 1 year in 10 sees frost after that.
Eagle Butte against the rest of the dataset
Eagle Butte's growing season runs about 141 days, ranking 36,924 of 40,283 US ZIP codes measured here, longest to shortest. Within SD, it ranks 292 of 378.
Learn more
Two guides worth reading on 57630: the frost range, on how to read the range around Eagle Butte's dates instead of trusting one, and local microclimates, on what one yard in Eagle Butte can differ from the 57630 normal.