Alanson, MI 49749 Frost Dates
Alanson, MI: when does the frost end?
Typically, the last spring freeze lands around 05/31, roughly 276 days out. Fall's first freeze usually shows up around 09/18, roughly 108 days after the last spring frost.
Zone 4b (-25 to -20°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 Alanson, not a forecast for this year.
Stretching the season past the first frost
With roughly 3 weeks until Alanson's first fall frost, a row cover or cold frame is what stretches the last few weeks of harvest here.
Why 05/31 isn't a guarantee
05/31 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 05/16 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 06/21 and only about 1 year in 10 sees frost after that.
Alanson against the rest of the dataset
About 108 days separate Alanson's last and first frost, putting it 39,548 of 40,283 ZIP codes nationally. Within MI, it ranks 1,136 of 1,153.
Learn more
Before leaning on 49749's figures: the frost range explains how to read the range around Alanson's dates instead of trusting one, while local microclimates explains what one yard in Alanson can differ from the 49749 normal.