Seneca, OR 97904 Frost Dates
Seneca, OR: when does the frost end?
Around 06/05 is the usual last spring frost, about 281 days away. Fall's first freeze usually shows up around 09/05, roughly 91 days after the last spring frost.
The USDA Plant Hardiness Zone Map puts Seneca 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 1 week until Seneca's first fall frost, a row cover or cold frame is what stretches the last few weeks of harvest here.
The actual range around Seneca's last frost
06/05 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 05/17 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 06/26 and only about 1 year in 10 sees frost after that.
Seneca against the rest of the dataset
At roughly 91 frost-free days, Seneca places 39,909 of 40,283 ZIP codes in this dataset. Within OR, it ranks 435 of 463.
Learn more
Before leaning on 97904's figures: the frost range explains how to read the range around Seneca's dates instead of trusting one, while local microclimates explains what one yard in Seneca can differ from the 97904 normal.