Tigard, OR 97223 Frost Dates
97223, near Tigard, OR: the frost window
Typically, the last spring freeze lands around 02/11, roughly 167 days out. Fall's first freeze usually shows up around 12/05, roughly 303 days after the last spring frost.
The USDA Plant Hardiness Zone Map puts Tigard 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
Tigard's growing season runs out in roughly 14 weeks — a cold frame or greenhouse kit is the usual way to keep cool-weather crops going past the first frost.
Why 02/11 isn't a guarantee
02/11 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 03/05 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 12/26 and only about 1 year in 10 sees frost after that.
Tigard against the rest of the dataset
Tigard's growing season runs about 303 days, ranking 3,777 of 40,283 US ZIP codes measured here, longest to shortest. Within OR, it ranks 24 of 463.
Learn more
Two guides worth reading on 97223: local microclimates, on what one yard in Tigard can differ from the 97223 normal, and zone vs. frost date, on why Zone 9a and Tigard's frost date answer different questions.