Gresham, OR 97030 Frost Dates
97030, near Gresham, OR: the frost window
Typically, the last spring freeze lands around 03/16, roughly 200 days out. Fall's first freeze usually shows up around 11/20, roughly 250 days after the last spring frost.
The USDA Plant Hardiness Zone Map puts Gresham in Zone 9a (20 to 25°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
Gresham's growing season runs out in roughly 12 weeks — a cold frame or greenhouse kit is the usual way to keep cool-weather crops going past the first frost.
Why 03/16 isn't a guarantee
03/16 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 02/18 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 04/12 and only about 1 year in 10 sees frost after that.
Gresham against the rest of the dataset
About 250 days separate Gresham's last and first frost, putting it 7,417 of 40,283 ZIP codes nationally. Within OR, it ranks 63 of 463.
Learn more
Two guides worth reading on 97030: the frost range, on how to read the range around Gresham's dates instead of trusting one, and local microclimates, on what one yard in Gresham can differ from the 97030 normal.