St. Ignace, MI 49780 Frost Dates
49780, near St. Ignace, MI: the frost window
The last spring frost here typically falls around 06/01, about 277 days from today. Fall's first freeze usually shows up around 09/21, roughly 110 days after the last spring frost.
St. Ignace sits in USDA Zone 4b (-25 to -20°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
St. Ignace'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 St. Ignace's last frost
06/01 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 05/18 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 06/20 and only about 1 year in 10 sees frost after that.
St. Ignace against the rest of the dataset
At roughly 110 frost-free days, St. Ignace places 39,505 of 40,283 ZIP codes in this dataset. Within MI, it ranks 1,130 of 1,153.
Learn more
Two guides worth reading on 49780: local microclimates, on what one yard in St. Ignace can differ from the 49780 normal, and zone vs. frost date, on why Zone 4b and St. Ignace's frost date answer different questions.