Portland, OR 97209 Frost Dates
When can you plant in Portland, OR?
Around 03/13 is the usual last spring frost, about 197 days away. The first fall frost typically arrives around 11/19, about 247 frost-free days later.
Zone 9a (20 to 25°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.
What to do before the first frost
About 12 weeks of growing season left in Portland before the first fall frost — a cold frame or row cover can stretch harvest weeks past that date.
The actual range around Portland's last frost
03/13 is the middle of 30 years of NOAA records, not a promise. Plant by 02/22 and you're betting against frost in roughly 9 years out of 10. 04/01 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Portland compares
Portland's growing season runs about 247 days, ranking 7,758 of 40,283 US ZIP codes measured here, longest to shortest. Within OR, it ranks 86 of 463.
Learn more
zone vs. frost date covers why Zone 9a and Portland's frost date answer different questions. the frost range covers how to read the range around Portland's dates instead of trusting one.