Murdo, SD 57559 Frost Dates
57559, near Murdo, SD: the frost window
Typically, the last spring freeze lands around 05/03, roughly 248 days out. Fall's first freeze usually shows up around 10/09, roughly 158 days after the last spring frost.
Murdo 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
Murdo'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 Murdo's last frost
05/03 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 04/19 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 05/16 and only about 1 year in 10 sees frost after that.
Murdo against the rest of the dataset
About 158 days separate Murdo's last and first frost, putting it 33,114 of 40,283 ZIP codes nationally. Within SD, it ranks 52 of 378.
Learn more
Two guides worth reading on 57559: zone vs. frost date, on why Zone 5a and Murdo's frost date answer different questions, and the frost range, on how to read the range around Murdo's dates instead of trusting one.