St. Ignace, MI 49760 Frost Dates
St. Ignace, MI: when does the frost end?
Around 05/23 is the usual last spring frost, about 268 days away. Fall's first freeze usually shows up around 09/30, roughly 130 days after the last spring frost.
Zone 5a (-20 to -15°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. Ignace, not a forecast for this year.
Stretching the season past the first frost
With roughly 5 weeks until St. Ignace's first fall frost, a row cover or cold frame is what stretches the last few weeks of harvest here.
How much risk comes with planting early here
05/23 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 05/06 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 06/06 and only about 1 year in 10 sees frost after that.
St. Ignace against the rest of the dataset
At roughly 130 frost-free days, St. Ignace places 38,378 of 40,283 ZIP codes in this dataset. Within MI, it ranks 1,030 of 1,153.
Learn more
Before leaning on 49760's figures: zone vs. frost date explains why Zone 5a and St. Ignace's frost date answer different questions, while the frost range explains how to read the range around St. Ignace's dates instead of trusting one.