Petersburg, MI 48140 Frost Dates
When can you plant in Petersburg, MI?
Typically, the last spring freeze lands around 04/27, roughly 242 days out. The first fall frost typically arrives around 10/21, about 176 frost-free days later.
Petersburg sits in USDA Zone 6a (-10 to -5°F average annual minimum). The dates above are NOAA's 1991-2020 normal at the nearest reporting station, a 30-year average, not a forecast.
What to do before the first frost
About 8 weeks of growing season left in Petersburg before the first fall frost — a cold frame or row cover can stretch harvest weeks past that date.
The actual range around Petersburg's last frost
04/27 is the middle of 30 years of NOAA records, not a promise. Plant by 04/14 and you're betting against frost in roughly 9 years out of 10. 05/13 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Petersburg compares
Petersburg's growing season runs about 176 days, ranking 26,532 of 40,283 US ZIP codes measured here, longest to shortest. Within MI, it ranks 125 of 1,153.
Learn more
zone vs. frost date covers why Zone 6a and Petersburg's frost date answer different questions. the frost range covers how to read the range around Petersburg's dates instead of trusting one.