Iron River, MI 49935 Frost Dates
49935, near Iron River, MI: the frost window
Typically, the last spring freeze lands around 06/06, roughly 282 days out. Fall's first freeze usually shows up around 09/09, roughly 94 days after the last spring frost.
Zone 4a (-30 to -25°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 Iron River, not a forecast for this year.
Stretching the season past the first frost
Iron River's growing season runs out in roughly 2 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 Iron River's last frost
06/06 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 05/23 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 07/07 and only about 1 year in 10 sees frost after that.
Iron River against the rest of the dataset
At roughly 94 frost-free days, Iron River places 39,824 of 40,283 ZIP codes in this dataset. Within MI, it ranks 1,147 of 1,153.
Learn more
Two guides worth reading on 49935: local microclimates, on what one yard in Iron River can differ from the 49935 normal, and zone vs. frost date, on why Zone 4a and Iron River's frost date answer different questions.