Owosso, MI 48867 Frost Dates
48867, near Owosso, MI: the frost window
The last spring frost here typically falls around 05/01, about 246 days from today. Fall's first freeze usually shows up around 10/15, roughly 164 days after the last spring frost.
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 Owosso, not a forecast for this year.
Stretching the season past the first frost
Owosso's growing season runs out in roughly 7 weeks — a cold frame or greenhouse kit is the usual way to keep cool-weather crops going past the first frost.
The actual range around Owosso's last frost
05/01 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 04/17 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 05/17 and only about 1 year in 10 sees frost after that.
Owosso against the rest of the dataset
Owosso's growing season runs about 164 days, ranking 30,867 of 40,283 US ZIP codes measured here, longest to shortest. Within MI, it ranks 472 of 1,153.
Learn more
Two guides worth reading on 48867: local microclimates, on what one yard in Owosso can differ from the 48867 normal, and zone vs. frost date, on why Zone 6a and Owosso's frost date answer different questions.