Green Isle, MN 55338 Frost Dates
Frost dates for Green Isle, MN, ZIP 55338
Typically, the last spring freeze lands around 04/24, roughly 239 days out. The first fall frost typically arrives around 10/15, about 170 frost-free days later.
Zone 4b (-25 to -20°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 Green Isle, not a forecast for this year.
What to do before the first frost
Zone 4b around Green Isle has about 7 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.
The actual range around Green Isle's last frost
04/24 is the middle of 30 years of NOAA records, not a promise. Plant by 04/09 and you're betting against frost in roughly 9 years out of 10. 05/08 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Green Isle compares
Green Isle's growing season runs about 170 days, ranking 29,164 of 40,283 US ZIP codes measured here, longest to shortest. Within MN, it ranks 86 of 943.
Learn more
local microclimates explains what one yard in Green Isle can differ from the 55338 normal, and zone vs. frost date explains why Zone 4b and Green Isle's frost date answer different questions.