Alanson, MI 49717 Frost Dates
Frost dates for Alanson, MI, ZIP 49717
The last spring frost here typically falls around 05/31, about 276 days from today. The first fall frost typically arrives around 09/18, about 108 frost-free days later.
Zone 5a (-20 to -15°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 5a around Alanson has about 3 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.
How much risk comes with planting early here
05/31 is the middle of 30 years of NOAA records, not a promise. Plant by 05/16 and you're betting against frost in roughly 9 years out of 10. 06/21 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Alanson compares
At roughly 108 frost-free days, Alanson places 39,547 of 40,283 ZIP codes in this dataset. Within MI, it ranks 1,135 of 1,153.
Learn more
local microclimates explains what one yard in Alanson can differ from the 49717 normal, and zone vs. frost date explains why Zone 5a and Alanson's frost date answer different questions.