Mason, MI 48909 Frost Dates
Frost dates for Mason, MI, ZIP 48909
The last spring frost here typically falls around 04/28, about 243 days from today. The first fall frost typically arrives around 10/17, about 173 frost-free days later.
The USDA Plant Hardiness Zone Map puts Mason in Zone 6a (-10 to -5°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 6a around Mason has about 7 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.
The actual range around Mason's last frost
04/28 is the middle of 30 years of NOAA records, not a promise. Plant by 04/13 and you're betting against frost in roughly 9 years out of 10. 05/16 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Mason compares
At roughly 173 frost-free days, Mason places 27,824 of 40,283 ZIP codes in this dataset. Within MI, it ranks 215 of 1,153.
Learn more
the frost range explains how to read the range around Mason's dates instead of trusting one, and local microclimates explains what one yard in Mason can differ from the 48909 normal.