Plymouth, MN 55484 Frost Dates
55484, near Plymouth, MN: the frost window
Around 04/29 is the usual last spring frost, about 244 days away. Fall's first freeze usually shows up around 10/12, roughly 163 days after the last spring frost.
The USDA Plant Hardiness Zone Map puts Plymouth in Zone 5a (-20 to -15°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
Plymouth'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.
Why 04/29 isn't a guarantee
04/29 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 04/15 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 05/12 and only about 1 year in 10 sees frost after that.
Plymouth against the rest of the dataset
About 163 days separate Plymouth's last and first frost, putting it 31,292 of 40,283 ZIP codes nationally. Within MN, it ranks 137 of 943.
Learn more
Two guides worth reading on 55484: local microclimates, on what one yard in Plymouth can differ from the 55484 normal, and zone vs. frost date, on why Zone 5a and Plymouth's frost date answer different questions.