Harbor Springs, MI 49737 Frost Dates
49737, near Harbor Springs, MI: the frost window
Around 05/15 is the usual last spring frost, about 260 days away. Fall's first freeze usually shows up around 10/16, roughly 152 days after the last spring frost.
The USDA Plant Hardiness Zone Map puts Harbor Springs in Zone 5b (-15 to -10°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
Harbor Springs'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.
How much risk comes with planting early here
05/15 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 04/30 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 05/30 and only about 1 year in 10 sees frost after that.
Harbor Springs against the rest of the dataset
About 152 days separate Harbor Springs's last and first frost, putting it 34,797 of 40,283 ZIP codes nationally. Within MI, it ranks 806 of 1,153.
Learn more
Two guides worth reading on 49737: zone vs. frost date, on why Zone 5b and Harbor Springs's frost date answer different questions, and the frost range, on how to read the range around Harbor Springs's dates instead of trusting one.