Grand River, IA 50108 Frost Dates
Grand River, IA: when does the frost end?
Typically, the last spring freeze lands around 04/23, roughly 238 days out. Fall's first freeze usually shows up around 10/17, roughly 176 days after the last spring frost.
The USDA Plant Hardiness Zone Map puts Grand River in Zone 5b (-15 to -10°F average annual minimum); frost dates are NOAA's 1991-2020 station normal, not this year's forecast.
Stretching the season past the first frost
With roughly 7 weeks until Grand River's first fall frost, a row cover or cold frame is what stretches the last few weeks of harvest here.
Why 04/23 isn't a guarantee
04/23 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 04/07 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.
Grand River against the rest of the dataset
About 176 days separate Grand River's last and first frost, putting it 26,647 of 40,283 ZIP codes nationally. Within IA, it ranks 159 of 1,042.
Learn more
Before leaning on 50108's figures: local microclimates explains what one yard in Grand River can differ from the 50108 normal, while zone vs. frost date explains why Zone 5b and Grand River's frost date answer different questions.