Swea City, IA 50590 Frost Dates
Swea City, IA: when does the frost end?
Around 04/25 is the usual last spring frost, about 240 days away. Fall's first freeze usually shows up around 10/14, roughly 171 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 Swea City, not a forecast for this year.
Stretching the season past the first frost
With roughly 7 weeks until Swea City's first fall frost, a row cover or cold frame is what stretches the last few weeks of harvest here.
Why 04/25 isn't a guarantee
04/25 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 04/12 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 05/06 and only about 1 year in 10 sees frost after that.
Swea City against the rest of the dataset
About 171 days separate Swea City's last and first frost, putting it 28,775 of 40,283 ZIP codes nationally. Within IA, it ranks 286 of 1,042.
Learn more
Before leaning on 50590's figures: the frost range explains how to read the range around Swea City's dates instead of trusting one, while local microclimates explains what one yard in Swea City can differ from the 50590 normal.