Glenham, SD 57631 Frost Dates
57631, near Glenham, SD: the frost window
The last spring frost here typically falls around 05/05, about 250 days from today. Fall's first freeze usually shows up around 10/04, roughly 150 days after the last spring frost.
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 Glenham, not a forecast for this year.
Stretching the season past the first frost
Glenham'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 Glenham's last frost
05/05 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 04/23 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 05/20 and only about 1 year in 10 sees frost after that.
Glenham against the rest of the dataset
About 150 days separate Glenham's last and first frost, putting it 35,452 of 40,283 ZIP codes nationally. Within SD, it ranks 175 of 378.
Learn more
Two guides worth reading on 57631: the frost range, on how to read the range around Glenham's dates instead of trusting one, and local microclimates, on what one yard in Glenham can differ from the 57631 normal.