Des Moines, IA 50321 Frost Dates
Des Moines, IA: when does the frost end?
Typically, the last spring freeze lands around 04/18, roughly 233 days out. Fall's first freeze usually shows up around 10/20, roughly 184 days after the last spring frost.
Zone 5b (-15 to -10°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 Des Moines, not a forecast for this year.
Stretching the season past the first frost
With roughly 8 weeks until Des Moines's first fall frost, a row cover or cold frame is what stretches the last few weeks of harvest here.
The actual range around Des Moines's last frost
04/18 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 04/04 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 05/02 and only about 1 year in 10 sees frost after that.
Des Moines against the rest of the dataset
About 184 days separate Des Moines's last and first frost, putting it 23,384 of 40,283 ZIP codes nationally. Within IA, it ranks 52 of 1,042.
Learn more
Before leaning on 50321's figures: zone vs. frost date explains why Zone 5b and Des Moines's frost date answer different questions, while the frost range explains how to read the range around Des Moines's dates instead of trusting one.