Osakis, MN 56360 Frost Dates
56360, near Osakis, MN: the frost window
Around 05/13 is the usual last spring frost, about 258 days away. Fall's first freeze usually shows up around 09/27, roughly 134 days after the last spring frost.
Zone 4b (-25 to -20°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 Osakis, not a forecast for this year.
Stretching the season past the first frost
Osakis's growing season runs out in roughly 4 weeks — a cold frame or greenhouse kit is the usual way to keep cool-weather crops going past the first frost.
Why 05/13 isn't a guarantee
05/13 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 05/01 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.
Osakis against the rest of the dataset
Osakis's growing season runs about 134 days, ranking 37,978 of 40,283 US ZIP codes measured here, longest to shortest. Within MN, it ranks 811 of 943.
Learn more
Two guides worth reading on 56360: local microclimates, on what one yard in Osakis can differ from the 56360 normal, and zone vs. frost date, on why Zone 4b and Osakis's frost date answer different questions.