Unionville, IA 52594 Frost Dates
When can you plant in Unionville, IA?
Around 04/18 is the usual last spring frost, about 233 days away. The first fall frost typically arrives around 10/23, about 187 frost-free days later.
The USDA Plant Hardiness Zone Map puts Unionville 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 8 weeks of growing season left in Unionville before the first fall frost — a cold frame or row cover can stretch harvest weeks past that date.
Why 04/18 isn't a guarantee
04/18 is the middle of 30 years of NOAA records, not a promise. Plant by 04/04 and you're betting against frost in roughly 9 years out of 10. 05/02 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Unionville compares
Unionville's growing season runs about 187 days, ranking 22,643 of 40,283 US ZIP codes measured here, longest to shortest. Within IA, it ranks 28 of 1,042.
Learn more
local microclimates covers what one yard in Unionville can differ from the 52594 normal. zone vs. frost date covers why Zone 5b and Unionville's frost date answer different questions.