St. Olaf, IA 52072 Frost Dates
Frost dates for St. Olaf, IA, ZIP 52072
Typically, the last spring freeze lands around 05/08, roughly 253 days out. The first fall frost typically arrives around 10/01, about 146 frost-free days later.
St. Olaf 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 St. Olaf has about 5 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 St. Olaf's last frost
05/08 is the middle of 30 years of NOAA records, not a promise. Plant by 04/24 and you're betting against frost in roughly 9 years out of 10. 05/22 is the safer bet, historically only a 1-in-10 chance of frost that late.
How St. Olaf compares
At roughly 146 frost-free days, St. Olaf places 36,146 of 40,283 ZIP codes in this dataset. Within IA, it ranks 1,036 of 1,042.
Learn more
local microclimates explains what one yard in St. Olaf can differ from the 52072 normal, and zone vs. frost date explains why Zone 5a and St. Olaf's frost date answer different questions.