Union Grove, WI 53139 Frost Dates
When can you plant in Union Grove, WI?
The last spring frost here typically falls around 05/05, about 250 days from today. The first fall frost typically arrives around 10/08, about 156 frost-free days later.
The USDA Plant Hardiness Zone Map puts Union Grove in Zone 5b (-15 to -10°F average annual minimum); frost dates are NOAA's 1991-2020 station normal, not this year's forecast.
What to do before the first frost
About 6 weeks of growing season left in Union Grove before the first fall frost — a cold frame or row cover can stretch harvest weeks past that date.
Why 05/05 isn't a guarantee
05/05 is the middle of 30 years of NOAA records, not a promise. Plant by 04/21 and you're betting against frost in roughly 9 years out of 10. 05/20 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Union Grove compares
Union Grove's growing season runs about 156 days, ranking 33,572 of 40,283 US ZIP codes measured here, longest to shortest. Within WI, it ranks 415 of 860.
Learn more
the frost range covers how to read the range around Union Grove's dates instead of trusting one. local microclimates covers what one yard in Union Grove can differ from the 53139 normal.