St. Joseph, MI 49085 Frost Dates
49085, near St. Joseph, MI: the frost window
Around 05/05 is the usual last spring frost, about 250 days away. Fall's first freeze usually shows up around 10/15, roughly 161 days after the last spring frost.
Zone 6b (-5 to 0°F average annual minimum) comes from the USDA Plant Hardiness Zone Map; the frost dates above are the 1991-2020 normal at the nearest reporting NOAA station for St. Joseph, not a forecast for this year.
Stretching the season past the first frost
St. Joseph'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.
Why 05/05 isn't a guarantee
05/05 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 05/26 and only about 1 year in 10 sees frost after that.
St. Joseph against the rest of the dataset
About 161 days separate St. Joseph's last and first frost, putting it 32,011 of 40,283 ZIP codes nationally. Within MI, it ranks 564 of 1,153.
Learn more
Two guides worth reading on 49085: zone vs. frost date, on why Zone 6b and St. Joseph's frost date answer different questions, and the frost range, on how to read the range around St. Joseph's dates instead of trusting one.