Forest Grove, OR 97298 Frost Dates
97298, near Forest Grove, OR: the frost window
The last spring frost here typically falls around 04/16, about 231 days from today. Fall's first freeze usually shows up around 10/26, roughly 192 days after the last spring frost.
The USDA Plant Hardiness Zone Map puts Forest Grove in Zone 8b (15 to 20°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
Forest Grove's growing season runs out in roughly 8 weeks — a cold frame or greenhouse kit is the usual way to keep cool-weather crops going past the first frost.
Why 04/16 isn't a guarantee
04/16 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 03/26 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 05/05 and only about 1 year in 10 sees frost after that.
Forest Grove against the rest of the dataset
About 192 days separate Forest Grove's last and first frost, putting it 20,184 of 40,283 ZIP codes nationally. Within OR, it ranks 270 of 463.
Learn more
Two guides worth reading on 97298: local microclimates, on what one yard in Forest Grove can differ from the 97298 normal, and zone vs. frost date, on why Zone 8b and Forest Grove's frost date answer different questions.