Oroville, WA 98844 Frost Dates
Oroville, WA: when does the frost end?
Around 05/06 is the usual last spring frost, about 251 days away. Fall's first freeze usually shows up around 10/06, roughly 151 days after the last spring frost.
The USDA Plant Hardiness Zone Map puts Oroville in Zone 6a (-10 to -5°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 6 weeks until Oroville'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
05/06 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 04/23 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 05/25 and only about 1 year in 10 sees frost after that.
Oroville against the rest of the dataset
About 151 days separate Oroville's last and first frost, putting it 35,065 of 40,283 ZIP codes nationally. Within WA, it ranks 598 of 700.
Learn more
Before leaning on 98844's figures: local microclimates explains what one yard in Oroville can differ from the 98844 normal, while zone vs. frost date explains why Zone 6a and Oroville's frost date answer different questions.