Harrison, MI 48625 Frost Dates
48625, near Harrison, MI: the frost window
Typically, the last spring freeze lands around 05/30, roughly 275 days out. Fall's first freeze usually shows up around 09/15, roughly 106 days after the last spring frost.
The USDA Plant Hardiness Zone Map puts Harrison in Zone 5a (-20 to -15°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
Harrison's growing season runs out in roughly 3 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 Harrison's last frost
05/30 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 05/12 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 06/19 and only about 1 year in 10 sees frost after that.
Harrison against the rest of the dataset
At roughly 106 frost-free days, Harrison places 39,584 of 40,283 ZIP codes in this dataset. Within MI, it ranks 1,137 of 1,153.
Learn more
Two guides worth reading on 48625: local microclimates, on what one yard in Harrison can differ from the 48625 normal, and zone vs. frost date, on why Zone 5a and Harrison's frost date answer different questions.