Charles City, IA 50616 Frost Dates
Frost dates for Charles City, IA, ZIP 50616
The last spring frost here typically falls around 04/30, about 245 days from today. The first fall frost typically arrives around 10/06, about 157 frost-free days later.
The USDA Plant Hardiness Zone Map puts Charles City in Zone 5a (-20 to -15°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
Zone 5a around Charles City 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 04/30 isn't a guarantee
04/30 is the middle of 30 years of NOAA records, not a promise. Plant by 04/15 and you're betting against frost in roughly 9 years out of 10. 05/14 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Charles City compares
About 157 days separate Charles City's last and first frost, putting it 33,297 of 40,283 ZIP codes nationally. Within IA, it ranks 830 of 1,042.
Learn more
the frost range explains how to read the range around Charles City's dates instead of trusting one, and local microclimates explains what one yard in Charles City can differ from the 50616 normal.