Happy Valley, OR 97086 Frost Dates
Happy Valley, OR: when does the frost end?
Around 03/16 is the usual last spring frost, about 200 days away. Fall's first freeze usually shows up around 11/20, roughly 250 days after the last spring frost.
The USDA Plant Hardiness Zone Map puts Happy Valley 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
With roughly 12 weeks until Happy Valley's first fall frost, a row cover or cold frame is what stretches the last few weeks of harvest here.
Why 03/16 isn't a guarantee
03/16 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 02/18 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 04/12 and only about 1 year in 10 sees frost after that.
Happy Valley against the rest of the dataset
Happy Valley's growing season runs about 250 days, ranking 7,461 of 40,283 US ZIP codes measured here, longest to shortest. Within OR, it ranks 67 of 463.
Learn more
Before leaning on 97086's figures: zone vs. frost date explains why Zone 8b and Happy Valley's frost date answer different questions, while the frost range explains how to read the range around Happy Valley's dates instead of trusting one.