Sanborn, IA 51248 Frost Dates
Sanborn, IA: when does the frost end?
Around 05/01 is the usual last spring frost, about 246 days away. Fall's first freeze usually shows up around 10/07, roughly 160 days after the last spring frost.
The USDA Plant Hardiness Zone Map puts Sanborn in Zone 5a (-20 to -15°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 6 weeks until Sanborn's first fall frost, a row cover or cold frame is what stretches the last few weeks of harvest here.
The actual range around Sanborn's last frost
05/01 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 04/16 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.
Sanborn against the rest of the dataset
At roughly 160 frost-free days, Sanborn places 32,414 of 40,283 ZIP codes in this dataset. Within IA, it ranks 761 of 1,042.
Learn more
Before leaning on 51248's figures: zone vs. frost date explains why Zone 5a and Sanborn's frost date answer different questions, while the frost range explains how to read the range around Sanborn's dates instead of trusting one.