DeWitt, IA 52733 Frost Dates
DeWitt, IA: when does the frost end?
Around 04/22 is the usual last spring frost, about 237 days away. Fall's first freeze usually shows up around 10/16, roughly 175 days after the last spring frost.
DeWitt sits in USDA Zone 5b (-15 to -10°F average annual minimum). The dates above are NOAA's 1991-2020 normal at the nearest reporting station, a 30-year average, not a forecast.
Stretching the season past the first frost
With roughly 7 weeks until DeWitt's first fall frost, a row cover or cold frame is what stretches the last few weeks of harvest here.
How much risk comes with planting early here
04/22 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 04/09 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 05/08 and only about 1 year in 10 sees frost after that.
DeWitt against the rest of the dataset
About 175 days separate DeWitt's last and first frost, putting it 26,873 of 40,283 ZIP codes nationally. Within IA, it ranks 171 of 1,042.
Learn more
Before leaning on 52733's figures: zone vs. frost date explains why Zone 5b and DeWitt's frost date answer different questions, while the frost range explains how to read the range around DeWitt's dates instead of trusting one.