Brookfield, WI 53045 Frost Dates
Frost dates for Brookfield, WI, ZIP 53045
The last spring frost here typically falls around 04/30, about 245 days from today. The first fall frost typically arrives around 10/14, about 164 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 Brookfield, not a forecast for this year.
What to do before the first frost
Zone 5b around Brookfield 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.
Why 04/30 isn't a guarantee
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. 05/15 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Brookfield compares
Brookfield's growing season runs about 164 days, ranking 30,844 of 40,283 US ZIP codes measured here, longest to shortest. Within WI, it ranks 205 of 860.
Learn more
the frost range explains how to read the range around Brookfield's dates instead of trusting one, and local microclimates explains what one yard in Brookfield can differ from the 53045 normal.