Tyndall, SD 57066 Frost Dates
57066, near Tyndall, SD: the frost window
The last spring frost here typically falls around 05/01, about 246 days from today. Fall's first freeze usually shows up around 10/07, roughly 158 days after the last spring frost.
Zone 5a (-20 to -15°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 Tyndall, not a forecast for this year.
Stretching the season past the first frost
Tyndall's growing season runs out in roughly 6 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 Tyndall's last frost
05/01 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 04/18 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.
Tyndall against the rest of the dataset
At roughly 158 frost-free days, Tyndall places 33,064 of 40,283 ZIP codes in this dataset. Within SD, it ranks 49 of 378.
Learn more
Two guides worth reading on 57066: local microclimates, on what one yard in Tyndall can differ from the 57066 normal, and zone vs. frost date, on why Zone 5a and Tyndall's frost date answer different questions.