Grand Marais, MN 55605 Frost Dates
When can you plant in Grand Marais, MN?
Typically, the last spring freeze lands around 05/24, roughly 269 days out. The first fall frost typically arrives around 09/29, about 127 frost-free days later.
Grand Marais sits in USDA Zone 4b (-25 to -20°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.
What to do before the first frost
About 5 weeks of growing season left in Grand Marais before the first fall frost — a cold frame or row cover can stretch harvest weeks past that date.
How much risk comes with planting early here
05/24 is the middle of 30 years of NOAA records, not a promise. Plant by 05/07 and you're betting against frost in roughly 9 years out of 10. 06/05 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Grand Marais compares
About 127 days separate Grand Marais's last and first frost, putting it 38,636 of 40,283 ZIP codes nationally. Within MN, it ranks 875 of 943.
Learn more
zone vs. frost date covers why Zone 4b and Grand Marais's frost date answer different questions. the frost range covers how to read the range around Grand Marais's dates instead of trusting one.