Lake Oswego, OR 97219 Frost Dates
97219, near Lake Oswego, 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.
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 Lake Oswego, not a forecast for this year.
Stretching the season past the first frost
Lake Oswego'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.
How much risk comes with planting early here
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.
Lake Oswego against the rest of the dataset
At roughly 303 frost-free days, Lake Oswego places 3,781 of 40,283 ZIP codes in this dataset. Within OR, it ranks 28 of 463.
Learn more
Two guides worth reading on 97219: zone vs. frost date, on why Zone 8b and Lake Oswego's frost date answer different questions, and the frost range, on how to read the range around Lake Oswego's dates instead of trusting one.