Seymour, IA 52590 Frost Dates
52590, near Seymour, IA: the frost window
Around 04/21 is the usual last spring frost, about 236 days away. Fall's first freeze usually shows up around 10/19, roughly 178 days after the last spring frost.
The USDA Plant Hardiness Zone Map puts Seymour 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
Seymour's growing season runs out in roughly 7 weeks — a cold frame or greenhouse kit is the usual way to keep cool-weather crops going past the first frost.
The actual range around Seymour's last frost
04/21 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.
Seymour against the rest of the dataset
Seymour's growing season runs about 178 days, ranking 25,858 of 40,283 US ZIP codes measured here, longest to shortest. Within IA, it ranks 115 of 1,042.
Learn more
Two guides worth reading on 52590: the frost range, on how to read the range around Seymour's dates instead of trusting one, and local microclimates, on what one yard in Seymour can differ from the 52590 normal.