Forest Grove, OR 97281 Frost Dates
Forest Grove, OR: when does the frost end?
Around 04/16 is the usual last spring frost, about 231 days away. 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 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
With roughly 8 weeks until Forest Grove's first fall frost, a row cover or cold frame is what stretches the last few weeks of harvest here.
How much risk comes with planting early here
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
At roughly 192 frost-free days, Forest Grove places 20,182 of 40,283 ZIP codes in this dataset. Within OR, it ranks 268 of 463.
Learn more
Before leaning on 97281's figures: zone vs. frost date explains why Zone 9a and Forest Grove's frost date answer different questions, while the frost range explains how to read the range around Forest Grove's dates instead of trusting one.