The National Weather Service has issued a cold weather advisory from midnight through 10 a.m. Thursday.

The advisory covers many areas from the south Washington Cascade Foothills through the southern Willamette Valley.

The weather service is warning residents some areas could see temperatures drop into the mid-20s overnight, with wind chills as low as 20 degrees.

Cold Weather Advisories are in effect for areas highlighted in blue on the map. These areas can expect wind chill temps as low as 20°F. While temperatures are not quite as cold in Portland & near the western Columbia River Gorge, it will still be quite chilly. Stay warm! pic.twitter.com/RURFZnYq2y

— NWS Portland (@NWSPortland) January 21, 2026

David Bishop is a meteorologist with the National Weather Service in Portland. He said it could potentially be one of the coldest nights the region has seen so far this winter.

“Things that you have to consider when we’re getting down to those temperatures is there is the possibility for hypothermia, maybe even some frostbite in some areas,” he said.

Bishop said people who are venturing outside should prepare for the cold by dressing warmly and covering any exposed skin. He recommended checking on older family members and friends as well as outdoor pets.

Bishop also stressed the importance of using heating devices safely as a way to prevent possible fires or other hazards.

“If you are going to be using a portable heater [make sure] that it’s used correctly,” Bishop said. “Don’t pull your generators or any grills inside because of carbon monoxide and carbon dioxide [risks].”

Meanwhile, a freezing fog advisory is in effect until 10 a.m. Thursday for Wallowa County. Forecasters with the NWS said frost and freezing conditions could kill crops and other sensitive vegetation, and cause hazardous driving conditions.

In Southern Oregon, some areas remain under an air stagnation advisory, including Jackson, Klamath and Lake counties. Stagnant air can trap pollutants near the surface where people can easily breathe them in.

Young children and people with heart or lung problems are advised to stay indoors while air quality is poor. That advisory is expected to last through Friday afternoon.

An air stagnation advisory is also in effect for portions of northeast and southeast Oregon until 5 a.m. Friday.

News Source : https://www.opb.org/article/2026/01/21/cold-weather-advisory-southwest-washington-oregon/