Greenfield, WI 53228 Frost Dates
53228, near Greenfield, WI: the frost window
The last spring frost here typically falls around 05/03, about 248 days from today. Fall's first freeze usually shows up around 10/14, roughly 162 days after the last spring frost.
Greenfield sits in USDA Zone 5b (-15 to -10°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.
Stretching the season past the first frost
Greenfield's growing season runs out in roughly 7 weeks — a cold frame or greenhouse kit is the usual way to keep cool-weather crops going past the first frost.
Why 05/03 isn't a guarantee
05/03 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 04/18 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 05/19 and only about 1 year in 10 sees frost after that.
Greenfield against the rest of the dataset
Greenfield's growing season runs about 162 days, ranking 31,628 of 40,283 US ZIP codes measured here, longest to shortest. Within WI, it ranks 256 of 860.
Learn more
Two guides worth reading on 53228: local microclimates, on what one yard in Greenfield can differ from the 53228 normal, and zone vs. frost date, on why Zone 5b and Greenfield's frost date answer different questions.