Grand Blanc, MI 48439 Frost Dates
Grand Blanc, MI: when does the frost end?
Around 05/06 is the usual last spring frost, about 251 days away. Fall's first freeze usually shows up around 10/10, roughly 155 days after the last spring frost.
The USDA Plant Hardiness Zone Map puts Grand Blanc in Zone 6a (-10 to -5°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
With roughly 6 weeks until Grand Blanc's first fall frost, a row cover or cold frame is what stretches the last few weeks of harvest here.
Why 05/06 isn't a guarantee
05/06 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 04/21 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 05/23 and only about 1 year in 10 sees frost after that.
Grand Blanc against the rest of the dataset
Grand Blanc's growing season runs about 155 days, ranking 33,944 of 40,283 US ZIP codes measured here, longest to shortest. Within MI, it ranks 775 of 1,153.
Learn more
Before leaning on 48439's figures: zone vs. frost date explains why Zone 6a and Grand Blanc's frost date answer different questions, while the frost range explains how to read the range around Grand Blanc's dates instead of trusting one.