Martin, SD 57551 Frost Dates
57551, near Martin, SD: the frost window
Typically, the last spring freeze lands around 05/14, roughly 259 days out. Fall's first freeze usually shows up around 10/01, roughly 139 days after the last spring frost.
Martin 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
Martin'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.
How much risk comes with planting early here
05/14 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 05/03 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 05/28 and only about 1 year in 10 sees frost after that.
Martin against the rest of the dataset
At roughly 139 frost-free days, Martin places 37,252 of 40,283 ZIP codes in this dataset. Within SD, it ranks 316 of 378.
Learn more
Two guides worth reading on 57551: local microclimates, on what one yard in Martin can differ from the 57551 normal, and zone vs. frost date, on why Zone 5a and Martin's frost date answer different questions.