Alpena, MI 49707 Frost Dates
When can you plant in Alpena, MI?
The last spring frost here typically falls around 05/05, about 250 days from today. The first fall frost typically arrives around 10/17, about 163 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 Alpena, not a forecast for this year.
What to do before the first frost
About 7 weeks of growing season left in Alpena before the first fall frost — a cold frame or row cover can stretch harvest weeks past that date.
The actual range around Alpena's last frost
05/05 is the middle of 30 years of NOAA records, not a promise. Plant by 04/21 and you're betting against frost in roughly 9 years out of 10. 05/21 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Alpena compares
About 163 days separate Alpena's last and first frost, putting it 31,357 of 40,283 ZIP codes nationally. Within MI, it ranks 513 of 1,153.
Learn more
local microclimates covers what one yard in Alpena can differ from the 49707 normal. zone vs. frost date covers why Zone 5b and Alpena's frost date answer different questions.