Sault Ste. Marie, MI 49783 Frost Dates
Frost dates for Sault Ste. Marie, MI, ZIP 49783
Typically, the last spring freeze lands around 05/09, roughly 254 days out. The first fall frost typically arrives around 10/11, about 151 frost-free days later.
The USDA Plant Hardiness Zone Map puts Sault Ste. Marie in Zone 4b (-25 to -20°F average annual minimum); frost dates are NOAA's 1991-2020 station normal, not this year's forecast.
What to do before the first frost
Zone 4b around Sault Ste. Marie has about 6 weeks left before the first fall frost — that's the usual window to get a cold frame up if you want to keep harvesting past it.
Why 05/09 isn't a guarantee
05/09 is the middle of 30 years of NOAA records, not a promise. Plant by 04/27 and you're betting against frost in roughly 9 years out of 10. 05/27 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Sault Ste. Marie compares
At roughly 151 frost-free days, Sault Ste. Marie places 34,964 of 40,283 ZIP codes in this dataset. Within MI, it ranks 811 of 1,153.
Learn more
local microclimates explains what one yard in Sault Ste. Marie can differ from the 49783 normal, and zone vs. frost date explains why Zone 4b and Sault Ste. Marie's frost date answer different questions.