The National Weather Service has issued an extreme heat watch with high temperatures between 95 and 100 degrees Fahrenheit expected across the Portland-Vancouver metro area, the Columbia River Gorge and much of the Willamette Valley.

The advisory goes into effect Friday morning through late Sunday night.

NWS meteorologist Colby Neuman said extreme heat events this late in the summer are rare and much more common in June and July.

“As we go into the second half of August, the odds of us getting to, let’s say, around 100 [degrees] really decrease dramatically, just based off of what’s happened historically,” Neuman said.

No air conditioning? Here’s how to stay cool in Oregon, Southwest Washington during a heat wave

But what’s really unusual this time is the duration. Neuman said while the chance is low — less than 20% — high temperatures could extend well into next week, up to a five-day heat event.

“Most of our heat events are usually two days,” Neuman said. “Three days is on the upper end of what’s sort of normal. When we start looking at four- or five-day heat events, those are much rarer, even in July… It’s a low probability of that happening, but it’s not out of the question at this point.”

That’s concerning for people living without air conditioning.

“Just because their home continues to heat up progressively more and more each day,” he said. “That can bring sort of compounding effects, especially for older folks, people that have medical conditions or [are] susceptible to heat-related illnesses.”

In 2021, a record-shattering heat dome plunged Portland into over 100-degree weather for several days, causing nearly 100 deaths, most of them in Multnomah County. Since then, Portland has ramped up preparation for extreme heat, including creating a program offering free air conditioners to residents.

Where to stay cool in Oregon, Southwest Washington during extreme heat

Multnomah County Communications Coordinator Jessica Morkert-Shibley said they’ve also been preparing for extreme heat events like this for several years.

“Since 2021, really, we have been very focused on providing cool spaces for our community, and it’s been part of our mission.”

Renee Curtis with the Department of County Human Services also clarified that cooling spaces are not the same as emergency cooling centers.

Emergency cooling centers are designated, county-run locations, and are not regularly open. When they are, they offer relief during the hottest part of the day during milder heat events and all day during more severe events. The county’s website has more information about how and when officials decide to open the centers.

Cooling spaces are generic locations where people can find relief, including county libraries, pools, community centers and interactive fountains and splash pads.

One example is the Gresham Senior Center, which provides seniors — who are among the most vulnerable to heat-related illnesses — with air conditioning and a relief from the extreme heat.

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Center director Scott Harden said the hot weather, combined with the isolation many seniors face, is a compounded health risk that his program tries to address.

“We just offer a chance to stay cool and a chance to connect with community, because you know when you live alone, the heat isn’t the only health risk,” Harden said.

Harden said two recent possible heat-related deaths in Multnomah County illustrate the double danger heat and isolation pose to some seniors.

County officials will continue to monitor the weather and decide if and when to open cooling centers.

News Source : https://www.opb.org/article/2025/08/20/oregon-southwest-washington-another-heatwave/