Forest Grove, OR 97116 Frost Dates
Frost dates for Forest Grove, OR, ZIP 97116
The last spring frost here typically falls around 04/16, about 231 days from today. The first fall frost typically arrives around 10/26, about 192 frost-free days later.
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.
What to do before the first frost
Zone 8b around Forest Grove has about 8 weeks left before the first fall frost — that's the usual window to get a cold frame up if you want to keep harvesting past it.
Why 04/16 isn't a guarantee
04/16 is the middle of 30 years of NOAA records, not a promise. Plant by 03/26 and you're betting against frost in roughly 9 years out of 10. 05/05 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Forest Grove compares
Forest Grove's growing season runs about 192 days, ranking 20,181 of 40,283 US ZIP codes measured here, longest to shortest. Within OR, it ranks 267 of 463.
Learn more
local microclimates explains what one yard in Forest Grove can differ from the 97116 normal, and zone vs. frost date explains why Zone 8b and Forest Grove's frost date answer different questions.