Hiawatha, IA 52233 Frost Dates
Frost dates for Hiawatha, IA, ZIP 52233
The last spring frost here typically falls around 04/28, about 243 days from today. The first fall frost typically arrives around 10/12, about 166 frost-free days later.
Hiawatha 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 Hiawatha 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 04/14 and you're betting against frost in roughly 9 years out of 10. 05/13 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Hiawatha compares
Hiawatha's growing season runs about 166 days, ranking 30,353 of 40,283 US ZIP codes measured here, longest to shortest. Within IA, it ranks 451 of 1,042.
Learn more
the frost range explains how to read the range around Hiawatha's dates instead of trusting one, and local microclimates explains what one yard in Hiawatha can differ from the 52233 normal.