Portland, IN 47371 Frost Dates
47371, near Portland, IN: the frost window
Typically, the last spring freeze lands around 04/28, roughly 243 days out. Fall's first freeze usually shows up around 10/15, roughly 171 days after the last spring frost.
The USDA Plant Hardiness Zone Map puts Portland in Zone 6a (-10 to -5°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
Portland'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.
How much risk comes with planting early here
04/28 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 04/13 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 05/14 and only about 1 year in 10 sees frost after that.
Portland against the rest of the dataset
About 171 days separate Portland's last and first frost, putting it 28,625 of 40,283 ZIP codes nationally. Within IN, it ranks 759 of 927.
Learn more
Two guides worth reading on 47371: the frost range, on how to read the range around Portland's dates instead of trusting one, and local microclimates, on what one yard in Portland can differ from the 47371 normal.