Flat Rock, MI 48134 Frost Dates
48134, near Flat Rock, MI: the frost window
Typically, the last spring freeze lands around 04/27, roughly 242 days out. Fall's first freeze usually shows up around 10/20, roughly 176 days after the last spring frost.
The USDA Plant Hardiness Zone Map puts Flat Rock in Zone 6b (-5 to 0°F average annual minimum); frost dates are NOAA's 1991-2020 station normal, not this year's forecast.
Stretching the season past the first frost
Flat Rock's growing season runs out in roughly 8 weeks — a cold frame or greenhouse kit is the usual way to keep cool-weather crops going past the first frost.
How much risk comes with planting early here
04/27 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 04/12 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 05/13 and only about 1 year in 10 sees frost after that.
Flat Rock against the rest of the dataset
Flat Rock's growing season runs about 176 days, ranking 26,408 of 40,283 US ZIP codes measured here, longest to shortest. Within MI, it ranks 117 of 1,153.
Learn more
Two guides worth reading on 48134: zone vs. frost date, on why Zone 6b and Flat Rock's frost date answer different questions, and the frost range, on how to read the range around Flat Rock's dates instead of trusting one.