St. Martin, MN 56302 Frost Dates
When can you plant in St. Martin, MN?
Typically, the last spring freeze lands around 05/03, roughly 248 days out. The first fall frost typically arrives around 10/07, about 155 frost-free days later.
St. Martin 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 6 weeks of growing season left in St. Martin 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
05/03 is the middle of 30 years of NOAA records, not a promise. Plant by 04/21 and you're betting against frost in roughly 9 years out of 10. 05/17 is the safer bet, historically only a 1-in-10 chance of frost that late.
How St. Martin compares
At roughly 155 frost-free days, St. Martin places 34,123 of 40,283 ZIP codes in this dataset. Within MN, it ranks 366 of 943.
Learn more
local microclimates covers what one yard in St. Martin can differ from the 56302 normal. zone vs. frost date covers why Zone 4b and St. Martin's frost date answer different questions.