Portland, OR 97239 Frost Dates
Portland, OR: when does the frost end?
The last spring frost here typically falls around 02/11, about 167 days from today. Fall's first freeze usually shows up around 12/05, roughly 303 days after the last spring frost.
Zone 8b (15 to 20°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 Portland, not a forecast for this year.
Stretching the season past the first frost
With roughly 14 weeks until Portland's first fall frost, a row cover or cold frame is what stretches the last few weeks of harvest here.
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.
Portland against the rest of the dataset
About 303 days separate Portland's last and first frost, putting it 3,766 of 40,283 ZIP codes nationally. Within OR, it ranks 13 of 463.
Learn more
Before leaning on 97239's figures: the frost range explains how to read the range around Portland's dates instead of trusting one, while local microclimates explains what one yard in Portland can differ from the 97239 normal.