Rothsay, MN 56579 Frost Dates
56579, near Rothsay, MN: the frost window
Around 05/05 is the usual last spring frost, about 250 days away. Fall's first freeze usually shows up around 10/03, roughly 149 days after the last spring frost.
Rothsay 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
Rothsay's growing season runs out in roughly 5 weeks — a cold frame or greenhouse kit is the usual way to keep cool-weather crops going past the first frost.
How much risk comes with planting early here
05/05 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 05/20 and only about 1 year in 10 sees frost after that.
Rothsay against the rest of the dataset
Rothsay's growing season runs about 149 days, ranking 35,558 of 40,283 US ZIP codes measured here, longest to shortest. Within MN, it ranks 568 of 943.
Learn more
Two guides worth reading on 56579: zone vs. frost date, on why Zone 4a and Rothsay's frost date answer different questions, and the frost range, on how to read the range around Rothsay's dates instead of trusting one.