Marshall, MN 56258 Frost Dates
56258, near Marshall, MN: the frost window
The last spring frost here typically falls around 05/05, about 250 days from today. Fall's first freeze usually shows up around 10/03, roughly 150 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 Marshall, not a forecast for this year.
Stretching the season past the first frost
Marshall'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.
The actual range around Marshall's last frost
05/05 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 04/21 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 05/18 and only about 1 year in 10 sees frost after that.
Marshall against the rest of the dataset
About 150 days separate Marshall's last and first frost, putting it 35,254 of 40,283 ZIP codes nationally. Within MN, it ranks 513 of 943.
Learn more
Two guides worth reading on 56258: zone vs. frost date, on why Zone 5a and Marshall's frost date answer different questions, and the frost range, on how to read the range around Marshall's dates instead of trusting one.