Lannon, WI 53046 Frost Dates
Frost dates for Lannon, WI, ZIP 53046
Around 04/30 is the usual last spring frost, about 245 days away. The first fall frost typically arrives around 10/16, about 167 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 Lannon, not a forecast for this year.
What to do before the first frost
Zone 5b around Lannon 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
04/30 is the middle of 30 years of NOAA records, not a promise. Plant by 04/16 and you're betting against frost in roughly 9 years out of 10. 05/16 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Lannon compares
At roughly 167 frost-free days, Lannon places 30,026 of 40,283 ZIP codes in this dataset. Within WI, it ranks 165 of 860.
Learn more
local microclimates explains what one yard in Lannon can differ from the 53046 normal, and zone vs. frost date explains why Zone 5b and Lannon's frost date answer different questions.