Platte, SD 57369 Frost Dates
Platte, SD: when does the frost end?
Around 04/30 is the usual last spring frost, about 245 days away. Fall's first freeze usually shows up around 10/08, roughly 159 days after the last spring frost.
The USDA Plant Hardiness Zone Map puts Platte in Zone 5a (-20 to -15°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
With roughly 6 weeks until Platte's first fall frost, a row cover or cold frame is what stretches the last few weeks of harvest here.
Why 04/30 isn't a guarantee
04/30 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 04/16 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.
Platte against the rest of the dataset
At roughly 159 frost-free days, Platte places 32,693 of 40,283 ZIP codes in this dataset. Within SD, it ranks 37 of 378.
Learn more
Before leaning on 57369's figures: zone vs. frost date explains why Zone 5a and Platte's frost date answer different questions, while the frost range explains how to read the range around Platte's dates instead of trusting one.