Ann Arbor, MI 48109 Frost Dates
When can you plant in Ann Arbor, MI?
The last spring frost here typically falls around 05/03, about 248 days from today. The first fall frost typically arrives around 10/13, about 160 frost-free days later.
Zone 6a (-10 to -5°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 Ann Arbor, not a forecast for this year.
What to do before the first frost
About 7 weeks of growing season left in Ann Arbor before the first fall frost — a cold frame or row cover can stretch harvest weeks past that date.
The actual range around Ann Arbor's last frost
05/03 is the middle of 30 years of NOAA records, not a promise. Plant by 04/20 and you're betting against frost in roughly 9 years out of 10. 05/20 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Ann Arbor compares
About 160 days separate Ann Arbor's last and first frost, putting it 32,190 of 40,283 ZIP codes nationally. Within MI, it ranks 614 of 1,153.
Learn more
the frost range covers how to read the range around Ann Arbor's dates instead of trusting one. local microclimates covers what one yard in Ann Arbor can differ from the 48109 normal.