Brookston, MN 55702 Frost Dates
55702, near Brookston, MN: the frost window
The last spring frost here typically falls around 05/29, about 274 days from today. Fall's first freeze usually shows up around 09/18, roughly 111 days after the last spring frost.
Brookston sits in USDA Zone 4a (-30 to -25°F average annual minimum). The dates above are NOAA's 1991-2020 normal at the nearest reporting station, a 30-year average, not a forecast.
Stretching the season past the first frost
Brookston's growing season runs out in roughly 3 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 Brookston's last frost
05/29 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 05/14 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 06/13 and only about 1 year in 10 sees frost after that.
Brookston against the rest of the dataset
At roughly 111 frost-free days, Brookston places 39,486 of 40,283 ZIP codes in this dataset. Within MN, it ranks 911 of 943.
Learn more
Two guides worth reading on 55702: zone vs. frost date, on why Zone 4a and Brookston's frost date answer different questions, and the frost range, on how to read the range around Brookston's dates instead of trusting one.