Onalaska, WI 54650 Frost Dates
Frost dates for Onalaska, WI, ZIP 54650
The last spring frost here typically falls around 04/23, about 238 days from today. The first fall frost typically arrives around 10/17, about 177 frost-free days later.
Onalaska sits in USDA Zone 5a (-20 to -15°F average annual minimum). The dates above are NOAA's 1991-2020 normal at the nearest reporting station, a 30-year average, not a forecast.
What to do before the first frost
Zone 5a around Onalaska 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.
How much risk comes with planting early here
04/23 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. 05/06 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Onalaska compares
Onalaska's growing season runs about 177 days, ranking 26,048 of 40,283 US ZIP codes measured here, longest to shortest. Within WI, it ranks 74 of 860.
Learn more
zone vs. frost date explains why Zone 5a and Onalaska's frost date answer different questions, and the frost range explains how to read the range around Onalaska's dates instead of trusting one.