Marion, IA 52497 Frost Dates
Marion, IA: when does the frost end?
Typically, the last spring freeze lands around 04/28, roughly 243 days out. Fall's first freeze usually shows up around 10/12, roughly 166 days after the last spring frost.
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 Marion, not a forecast for this year.
Stretching the season past the first frost
With roughly 6 weeks until Marion's first fall frost, a row cover or cold frame is what stretches the last few weeks of harvest here.
The actual range around Marion's last frost
04/28 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 04/14 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 05/13 and only about 1 year in 10 sees frost after that.
Marion against the rest of the dataset
About 166 days separate Marion's last and first frost, putting it 30,290 of 40,283 ZIP codes nationally. Within IA, it ranks 446 of 1,042.
Learn more
Before leaning on 52497's figures: the frost range explains how to read the range around Marion's dates instead of trusting one, while local microclimates explains what one yard in Marion can differ from the 52497 normal.