Hillsdale, MI 49266 Frost Dates
49266, near Hillsdale, MI: the frost window
Typically, the last spring freeze lands around 05/03, roughly 248 days out. Fall's first freeze usually shows up around 10/12, roughly 161 days after the last spring frost.
Hillsdale sits in USDA Zone 6a (-10 to -5°F average annual minimum). The dates above are NOAA's 1991-2020 normal at the nearest reporting station, a 30-year average, not a forecast.
Stretching the season past the first frost
Hillsdale's growing season runs out in roughly 6 weeks — a cold frame or greenhouse kit is the usual way to keep cool-weather crops going past the first frost.
Why 05/03 isn't a guarantee
05/03 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 04/20 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 05/19 and only about 1 year in 10 sees frost after that.
Hillsdale against the rest of the dataset
About 161 days separate Hillsdale's last and first frost, putting it 32,010 of 40,283 ZIP codes nationally. Within MI, it ranks 563 of 1,153.
Learn more
Two guides worth reading on 49266: zone vs. frost date, on why Zone 6a and Hillsdale's frost date answer different questions, and the frost range, on how to read the range around Hillsdale's dates instead of trusting one.