Belvidere, SD 57521 Frost Dates
Belvidere, SD: when does the frost end?
Around 05/12 is the usual last spring frost, about 257 days away. Fall's first freeze usually shows up around 09/28, roughly 138 days after the last spring frost.
Belvidere 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
With roughly 4 weeks until Belvidere's first fall frost, a row cover or cold frame is what stretches the last few weeks of harvest here.
Why 05/12 isn't a guarantee
05/12 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 04/30 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 05/26 and only about 1 year in 10 sees frost after that.
Belvidere against the rest of the dataset
At roughly 138 frost-free days, Belvidere places 37,487 of 40,283 ZIP codes in this dataset. Within SD, it ranks 337 of 378.
Learn more
Before leaning on 57521's figures: zone vs. frost date explains why Zone 5a and Belvidere's frost date answer different questions, while the frost range explains how to read the range around Belvidere's dates instead of trusting one.