Tolstoy, SD 57475 Frost Dates
57475, near Tolstoy, SD: the frost window
The last spring frost here typically falls around 05/07, about 252 days from today. Fall's first freeze usually shows up around 10/03, roughly 148 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 Tolstoy, not a forecast for this year.
Stretching the season past the first frost
Tolstoy'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.
Why 05/07 isn't a guarantee
05/07 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 04/24 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.
Tolstoy against the rest of the dataset
Tolstoy's growing season runs about 148 days, ranking 35,818 of 40,283 US ZIP codes measured here, longest to shortest. Within SD, it ranks 208 of 378.
Learn more
Two guides worth reading on 57475: the frost range, on how to read the range around Tolstoy's dates instead of trusting one, and local microclimates, on what one yard in Tolstoy can differ from the 57475 normal.