Oshkosh, WI 54901 Frost Dates
Frost dates for Oshkosh, WI, ZIP 54901
Around 04/24 is the usual last spring frost, about 239 days away. The first fall frost typically arrives around 10/20, about 178 frost-free days later.
Zone 5b (-15 to -10°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 Oshkosh, not a forecast for this year.
What to do before the first frost
Zone 5b around Oshkosh has about 8 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
04/24 is the middle of 30 years of NOAA records, not a promise. Plant by 04/10 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 Oshkosh compares
Oshkosh's growing season runs about 178 days, ranking 25,566 of 40,283 US ZIP codes measured here, longest to shortest. Within WI, it ranks 45 of 860.
Learn more
zone vs. frost date explains why Zone 5b and Oshkosh's frost date answer different questions, and the frost range explains how to read the range around Oshkosh's dates instead of trusting one.