West Union, IA 52175 Frost Dates
52175, near West Union, IA: the frost window
Around 05/04 is the usual last spring frost, about 249 days away. Fall's first freeze usually shows up around 10/04, roughly 151 days after the last spring frost.
Zone 5a (-20 to -15°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 West Union, not a forecast for this year.
Stretching the season past the first frost
West Union's growing season runs out in roughly 5 weeks — a cold frame or greenhouse kit is the usual way to keep cool-weather crops going past the first frost.
Why 05/04 isn't a guarantee
05/04 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 04/20 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 05/17 and only about 1 year in 10 sees frost after that.
West Union against the rest of the dataset
West Union's growing season runs about 151 days, ranking 35,047 of 40,283 US ZIP codes measured here, longest to shortest. Within IA, it ranks 966 of 1,042.
Learn more
Two guides worth reading on 52175: local microclimates, on what one yard in West Union can differ from the 52175 normal, and zone vs. frost date, on why Zone 5a and West Union's frost date answer different questions.