Richland, OR 97870 Frost Dates
97870, near Richland, OR: the frost window
Around 05/10 is the usual last spring frost, about 255 days away. Fall's first freeze usually shows up around 10/01, roughly 141 days after the last spring frost.
The USDA Plant Hardiness Zone Map puts Richland in Zone 6b (-5 to 0°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
Richland's growing season runs out in roughly 5 weeks — a cold frame or greenhouse kit is the usual way to keep cool-weather crops going past the first frost.
The actual range around Richland's last frost
05/10 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 04/27 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 05/29 and only about 1 year in 10 sees frost after that.
Richland against the rest of the dataset
About 141 days separate Richland's last and first frost, putting it 36,999 of 40,283 ZIP codes nationally. Within OR, it ranks 376 of 463.
Learn more
Two guides worth reading on 97870: local microclimates, on what one yard in Richland can differ from the 97870 normal, and zone vs. frost date, on why Zone 6b and Richland's frost date answer different questions.