Truro, IA 50257 Frost Dates
50257, near Truro, IA: the frost window
Around 04/30 is the usual last spring frost, about 245 days away. Fall's first freeze usually shows up around 10/03, roughly 157 days after the last spring frost.
Truro 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
Truro's growing season runs out in roughly 5 weeks — a cold frame or greenhouse kit is the usual way to keep cool-weather crops going past the first frost.
How much risk comes with planting early here
04/30 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 04/17 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 05/11 and only about 1 year in 10 sees frost after that.
Truro against the rest of the dataset
Truro's growing season runs about 157 days, ranking 33,422 of 40,283 US ZIP codes measured here, longest to shortest. Within IA, it ranks 847 of 1,042.
Learn more
Two guides worth reading on 50257: local microclimates, on what one yard in Truro can differ from the 50257 normal, and zone vs. frost date, on why Zone 5b and Truro's frost date answer different questions.