Waterville, IA 52170 Frost Dates
Frost dates for Waterville, IA, ZIP 52170
The last spring frost here typically falls around 05/02, about 247 days from today. The first fall frost typically arrives around 10/11, about 161 frost-free days later.
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 Waterville, not a forecast for this year.
What to do before the first frost
Zone 5a around Waterville 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 05/02 isn't a guarantee
05/02 is the middle of 30 years of NOAA records, not a promise. Plant by 04/17 and you're betting against frost in roughly 9 years out of 10. 05/16 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Waterville compares
About 161 days separate Waterville's last and first frost, putting it 32,182 of 40,283 ZIP codes nationally. Within IA, it ranks 756 of 1,042.
Learn more
the frost range explains how to read the range around Waterville's dates instead of trusting one, and local microclimates explains what one yard in Waterville can differ from the 52170 normal.