NWS Portland has issued Frost Advisories for two straight nights, Thursday night and Friday night, across northwest Oregon and southwest Washington.
A Freeze Watch is also in effect Friday night for the Willamette Valley and nearby foothills.
Temperatures as low as 33 to 36 degrees will cause frost, and 31 degrees is possible Friday night where the watch applies.
The alerts were issued at 6:55 p.m. PDT Wednesday.
Two Nights of Frost
First night: 11 p.m. Thursday to 9 a.m. PDT Friday.
Second night: 11 p.m. Friday to 9 a.m. PDT Saturday.
Frost could harm sensitive outdoor vegetation, and plants may be killed if left uncovered.
Both Nights: Tualatin Valley, Coast Range and Southwest Washington
Oregon: Tualatin Valley, the Central Oregon Coast Range and the Central Oregon Coast Range Lowlands.
Washington: Cowlitz County Lowlands, North Clark County Lowlands, South Washington Cascade Foothills and Willapa Hills.
Cities include Hillsboro, Sherwood, Tigard, Forest Grove, Longview, Kelso, Battle Ground and Ridgefield.
Willamette Valley: Frost, Then a Freeze Watch
Thursday night: Frost Advisory for the East and West Central Willamette Valley, the North Oregon Coast Range, and the Cascade foothills of Marion, Linn and Lane counties.
Friday night: a Freeze Watch replaces the advisory, with lows as cold as 31 degrees.
Frost and freezing temperatures could kill crops and damage unprotected outdoor plumbing.
Cities include Salem, Keizer, McMinnville, Dallas, Silverton, Stayton, Woodburn and Oakridge.
Friday Night Only: Portland Metro, Coast and Vancouver
Frost Advisory from 11 p.m. Friday to 9 a.m. PDT Saturday, with lows of 34 to 36 degrees.
Oregon: the Clatsop, Tillamook and Central Oregon coasts, Lower Columbia River, Inner, East and Outer Southeast Portland Metro, the West Columbia River Gorge above 500 feet, and Clackamas County Cascade foothills.
Washington: Inner Vancouver Metro and East Clark County Lowlands.
Cities include Portland, Gresham, Vancouver, Camas, Astoria, Seaside, Lincoln City, Newport and Oregon City.
How to Protect Plants
Take steps now to protect tender outdoor plants from the cold.
Move potted plants indoors if they are sensitive to cold.
Cover sensitive plants with lightweight cotton fabric, such as bedsheets or thin blankets, to retain heat.
Local forecasts and alerts: NWS Portland.
