Grand Marais, MN 55615 Frost Dates
55615, near Grand Marais, MN: the frost window
The last spring frost here typically falls around 05/26, about 271 days from today. Fall's first freeze usually shows up around 09/27, roughly 126 days after the last spring frost.
Zone 3b (-35 to -30°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 Grand Marais, not a forecast for this year.
Stretching the season past the first frost
Grand Marais'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.
How much risk comes with planting early here
05/26 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 05/09 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 06/06 and only about 1 year in 10 sees frost after that.
Grand Marais against the rest of the dataset
Grand Marais's growing season runs about 126 days, ranking 38,691 of 40,283 US ZIP codes measured here, longest to shortest. Within MN, it ranks 879 of 943.
Learn more
Two guides worth reading on 55615: local microclimates, on what one yard in Grand Marais can differ from the 55615 normal, and zone vs. frost date, on why Zone 3b and Grand Marais's frost date answer different questions.