Delmar, IA 52037 Frost Dates
Frost dates for Delmar, IA, ZIP 52037
Typically, the last spring freeze lands around 04/25, roughly 240 days out. The first fall frost typically arrives around 10/14, about 171 frost-free days later.
Delmar 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 Delmar has about 7 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 04/25 isn't a guarantee
04/25 is the middle of 30 years of NOAA records, not a promise. Plant by 04/11 and you're betting against frost in roughly 9 years out of 10. 05/09 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Delmar compares
At roughly 171 frost-free days, Delmar places 28,776 of 40,283 ZIP codes in this dataset. Within IA, it ranks 287 of 1,042.
Learn more
local microclimates explains what one yard in Delmar can differ from the 52037 normal, and zone vs. frost date explains why Zone 5a and Delmar's frost date answer different questions.