Lake Isabella, MI 49340 Frost Dates
49340, near Lake Isabella, MI: the frost window
The last spring frost here typically falls around 04/30, about 245 days from today. Fall's first freeze usually shows up around 10/20, roughly 171 days after the last spring frost.
The USDA Plant Hardiness Zone Map puts Lake Isabella in Zone 5b (-15 to -10°F average annual minimum); frost dates are NOAA's 1991-2020 station normal, not this year's forecast.
Stretching the season past the first frost
Lake Isabella's growing season runs out in roughly 8 weeks — a cold frame or greenhouse kit is the usual way to keep cool-weather crops going past the first frost.
Why 04/30 isn't a guarantee
04/30 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 04/17 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 05/16 and only about 1 year in 10 sees frost after that.
Lake Isabella against the rest of the dataset
Lake Isabella's growing season runs about 171 days, ranking 28,683 of 40,283 US ZIP codes measured here, longest to shortest. Within MI, it ranks 292 of 1,153.
Learn more
Two guides worth reading on 49340: zone vs. frost date, on why Zone 5b and Lake Isabella's frost date answer different questions, and the frost range, on how to read the range around Lake Isabella's dates instead of trusting one.