Alanson, MI 49722 Frost Dates
Frost dates for Alanson, MI, ZIP 49722
The last spring frost here typically falls around 05/16, about 261 days from today. The first fall frost typically arrives around 10/09, about 147 frost-free days later.
Zone 5b (-15 to -10°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 Alanson, not a forecast for this year.
What to do before the first frost
Zone 5b around Alanson 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 05/16 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. 05/31 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Alanson compares
At roughly 147 frost-free days, Alanson places 35,946 of 40,283 ZIP codes in this dataset. Within MI, it ranks 865 of 1,153.
Learn more
local microclimates explains what one yard in Alanson can differ from the 49722 normal, and zone vs. frost date explains why Zone 5b and Alanson's frost date answer different questions.