Plymouth, MN 55488 Frost Dates
55488, near Plymouth, MN: the frost window
The last spring frost here typically falls around 04/29, about 244 days from today. Fall's first freeze usually shows up around 10/12, roughly 163 days after the last spring frost.
Zone 5a (-20 to -15°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 Plymouth, not a forecast for this year.
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.
How much risk comes with planting early here
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
Plymouth's growing season runs about 163 days, ranking 31,296 of 40,283 US ZIP codes measured here, longest to shortest. Within MN, it ranks 141 of 943.
Learn more
Two guides worth reading on 55488: the frost range, on how to read the range around Plymouth's dates instead of trusting one, and local microclimates, on what one yard in Plymouth can differ from the 55488 normal.