Promise City, IA 52583 Frost Dates
Frost dates for Promise City, IA, ZIP 52583
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.
Zone 5b (-15 to -10°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 Promise City, not a forecast for this year.
What to do before the first frost
Zone 5b around Promise City has about 8 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.
The actual range around Promise City's last frost
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 Promise City compares
About 187 days separate Promise City's last and first frost, putting it 22,638 of 40,283 ZIP codes nationally. Within IA, it ranks 27 of 1,042.
Learn more
local microclimates explains what one yard in Promise City can differ from the 52583 normal, and zone vs. frost date explains why Zone 5b and Promise City's frost date answer different questions.