Winthrop, IA 50682 Frost Dates
Frost dates for Winthrop, IA, ZIP 50682
The last spring frost here typically falls around 04/30, about 245 days from today. The first fall frost typically arrives around 10/07, about 159 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 Winthrop, not a forecast for this year.
What to do before the first frost
Zone 5a around Winthrop 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.
The actual range around Winthrop's last frost
04/30 is the middle of 30 years of NOAA records, not a promise. Plant by 04/16 and you're betting against frost in roughly 9 years out of 10. 05/12 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Winthrop compares
At roughly 159 frost-free days, Winthrop places 32,707 of 40,283 ZIP codes in this dataset. Within IA, it ranks 786 of 1,042.
Learn more
the frost range explains how to read the range around Winthrop's dates instead of trusting one, and local microclimates explains what one yard in Winthrop can differ from the 50682 normal.