St. Ansgar, IA 50472 Frost Dates
Frost dates for St. Ansgar, IA, ZIP 50472
The last spring frost here typically falls around 04/30, about 245 days from today. The first fall frost typically arrives around 10/09, about 163 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 St. Ansgar, not a forecast for this year.
What to do before the first frost
Zone 5a around St. Ansgar 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 St. Ansgar's last frost
04/30 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. 05/12 is the safer bet, historically only a 1-in-10 chance of frost that late.
How St. Ansgar compares
St. Ansgar's growing season runs about 163 days, ranking 31,445 of 40,283 US ZIP codes measured here, longest to shortest. Within IA, it ranks 666 of 1,042.
Learn more
zone vs. frost date explains why Zone 5a and St. Ansgar's frost date answer different questions, and the frost range explains how to read the range around St. Ansgar's dates instead of trusting one.