St. Francis, SD 57570 Frost Dates
St. Francis, SD: when does the frost end?
Around 05/09 is the usual last spring frost, about 254 days away. Fall's first freeze usually shows up around 10/01, roughly 146 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 St. Francis, not a forecast for this year.
Stretching the season past the first frost
With roughly 5 weeks until St. Francis's first fall frost, a row cover or cold frame is what stretches the last few weeks of harvest here.
The actual range around St. Francis's last frost
05/09 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 04/28 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 05/21 and only about 1 year in 10 sees frost after that.
St. Francis against the rest of the dataset
About 146 days separate St. Francis's last and first frost, putting it 36,093 of 40,283 ZIP codes nationally. Within SD, it ranks 218 of 378.
Learn more
Before leaning on 57570's figures: zone vs. frost date explains why Zone 5a and St. Francis's frost date answer different questions, while the frost range explains how to read the range around St. Francis's dates instead of trusting one.