Rochester, MN 55901 Frost Dates
Frost dates for Rochester, MN, ZIP 55901
The last spring frost here typically falls around 05/12, about 257 days from today. The first fall frost typically arrives around 09/28, about 139 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 Rochester, not a forecast for this year.
What to do before the first frost
Zone 4b around Rochester has about 4 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
05/12 is the middle of 30 years of NOAA records, not a promise. Plant by 04/29 and you're betting against frost in roughly 9 years out of 10. 05/25 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Rochester compares
Rochester's growing season runs about 139 days, ranking 37,202 of 40,283 US ZIP codes measured here, longest to shortest. Within MN, it ranks 754 of 943.
Learn more
zone vs. frost date explains why Zone 4b and Rochester's frost date answer different questions, and the frost range explains how to read the range around Rochester's dates instead of trusting one.