Plymouth, MN 55458 Frost Dates
When can you plant in Plymouth, MN?
Around 04/29 is the usual last spring frost, about 244 days away. 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
About 6 weeks of growing season left in Plymouth before the first fall frost — a cold frame or row cover can stretch harvest weeks past that date.
The actual range around Plymouth's last frost
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
At roughly 163 frost-free days, Plymouth places 31,283 of 40,283 ZIP codes in this dataset. Within MN, it ranks 128 of 943.
Learn more
local microclimates covers what one yard in Plymouth can differ from the 55458 normal. zone vs. frost date covers why Zone 5a and Plymouth's frost date answer different questions.