Plymouth, MN 55474 Frost Dates
Frost dates for Plymouth, MN, ZIP 55474
The last spring frost here typically falls around 04/29, about 244 days from today. The first fall frost typically arrives around 10/12, about 163 frost-free days later.
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.
What to do before the first frost
Zone 5a around Plymouth has about 6 weeks left before the first fall frost — that's the usual window to get a cold frame up if you want to keep harvesting past it.
How much risk comes with planting early here
04/29 is the middle of 30 years of NOAA records, not a promise. Plant by 04/15 and you're betting against frost in roughly 9 years out of 10. 05/12 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Plymouth compares
Plymouth's growing season runs about 163 days, ranking 31,287 of 40,283 US ZIP codes measured here, longest to shortest. Within MN, it ranks 132 of 943.
Learn more
the frost range explains how to read the range around Plymouth's dates instead of trusting one, and local microclimates explains what one yard in Plymouth can differ from the 55474 normal.