Mentor, MN 56736 Frost Dates
Mentor, MN: when does the frost end?
Typically, the last spring freeze lands around 05/09, roughly 254 days out. Fall's first freeze usually shows up around 09/30, roughly 142 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 Mentor, not a forecast for this year.
Stretching the season past the first frost
With roughly 5 weeks until Mentor's first fall frost, a row cover or cold frame is what stretches the last few weeks of harvest here.
The actual range around Mentor's last frost
05/09 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 04/27 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 05/24 and only about 1 year in 10 sees frost after that.
Mentor against the rest of the dataset
Mentor's growing season runs about 142 days, ranking 36,842 of 40,283 US ZIP codes measured here, longest to shortest. Within MN, it ranks 704 of 943.
Learn more
Before leaning on 56736's figures: the frost range explains how to read the range around Mentor's dates instead of trusting one, while local microclimates explains what one yard in Mentor can differ from the 56736 normal.