Dayton, IA 50530 Frost Dates
Frost dates for Dayton, IA, ZIP 50530
Typically, the last spring freeze lands around 04/28, roughly 243 days out. The first fall frost typically arrives around 10/12, about 165 frost-free days later.
Dayton sits in USDA Zone 5a (-20 to -15°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.
What to do before the first frost
Zone 5a around Dayton has about 6 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 04/28 isn't a guarantee
04/28 is the middle of 30 years of NOAA records, not a promise. Plant by 04/13 and you're betting against frost in roughly 9 years out of 10. 05/11 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Dayton compares
Dayton's growing season runs about 165 days, ranking 30,661 of 40,283 US ZIP codes measured here, longest to shortest. Within IA, it ranks 525 of 1,042.
Learn more
local microclimates explains what one yard in Dayton can differ from the 50530 normal, and zone vs. frost date explains why Zone 5a and Dayton's frost date answer different questions.