Aitkin, MN 56431 Frost Dates
When can you plant in Aitkin, MN?
Typically, the last spring freeze lands around 05/16, roughly 261 days out. The first fall frost typically arrives around 09/28, about 133 frost-free days later.
Aitkin sits in USDA Zone 4a (-30 to -25°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 4 weeks of growing season left in Aitkin before the first fall frost — a cold frame or row cover can stretch harvest weeks past that date.
Why 05/16 isn't a guarantee
05/16 is the middle of 30 years of NOAA records, not a promise. Plant by 04/30 and you're betting against frost in roughly 9 years out of 10. 06/01 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Aitkin compares
About 133 days separate Aitkin's last and first frost, putting it 38,064 of 40,283 ZIP codes nationally. Within MN, it ranks 823 of 943.
Learn more
local microclimates covers what one yard in Aitkin can differ from the 56431 normal. zone vs. frost date covers why Zone 4a and Aitkin's frost date answer different questions.