Burt, IA 50522 Frost Dates
50522, near Burt, IA: the frost window
Typically, the last spring freeze lands around 04/27, roughly 242 days out. Fall's first freeze usually shows up around 10/07, roughly 164 days after the last spring frost.
Zone 5a (-20 to -15°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 Burt, not a forecast for this year.
Stretching the season past the first frost
Burt's growing season runs out in roughly 6 weeks — a cold frame or greenhouse kit is the usual way to keep cool-weather crops going past the first frost.
Why 04/27 isn't a guarantee
04/27 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 04/11 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 05/09 and only about 1 year in 10 sees frost after that.
Burt against the rest of the dataset
Burt's growing season runs about 164 days, ranking 31,142 of 40,283 US ZIP codes measured here, longest to shortest. Within IA, it ranks 621 of 1,042.
Learn more
Two guides worth reading on 50522: local microclimates, on what one yard in Burt can differ from the 50522 normal, and zone vs. frost date, on why Zone 5a and Burt's frost date answer different questions.