Alcester, SD 57001 Frost Dates
57001, near Alcester, SD: the frost window
Around 05/01 is the usual last spring frost, about 246 days away. Fall's first freeze usually shows up around 10/04, roughly 155 days after the last spring frost.
Alcester sits in USDA Zone 5a (-20 to -15°F average annual minimum). The dates above are NOAA's 1991-2020 normal at the nearest reporting station, a 30-year average, not a forecast.
Stretching the season past the first frost
Alcester'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.
How much risk comes with planting early here
05/01 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 04/17 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 05/14 and only about 1 year in 10 sees frost after that.
Alcester against the rest of the dataset
Alcester's growing season runs about 155 days, ranking 34,056 of 40,283 US ZIP codes measured here, longest to shortest. Within SD, it ranks 102 of 378.
Learn more
Two guides worth reading on 57001: zone vs. frost date, on why Zone 5a and Alcester's frost date answer different questions, and the frost range, on how to read the range around Alcester's dates instead of trusting one.