Duluth, MN 55806 Frost Dates
55806, near Duluth, MN: the frost window
Around 05/14 is the usual last spring frost, about 259 days away. Fall's first freeze usually shows up around 10/12, roughly 149 days after the last spring frost.
The USDA Plant Hardiness Zone Map puts Duluth in Zone 4b (-25 to -20°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
Duluth's growing season runs out in roughly 6 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 Duluth's last frost
05/14 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 04/24 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 06/01 and only about 1 year in 10 sees frost after that.
Duluth against the rest of the dataset
At roughly 149 frost-free days, Duluth places 35,475 of 40,283 ZIP codes in this dataset. Within MN, it ranks 560 of 943.
Learn more
Two guides worth reading on 55806: zone vs. frost date, on why Zone 4b and Duluth's frost date answer different questions, and the frost range, on how to read the range around Duluth's dates instead of trusting one.