PORTLAND, Ore. — The Pacific Northwest is once again battling an oppressive heat wave as temperatures soared close to 100 degrees in parts of Oregon and Washington state this week, the latest freak weather upending the lives of millions of Americans.

Portland’s mayor declared a “state of emergency” and rushed to open more cooling centers as temperatures climbed to 98 degrees on Thursday, 94 degrees on Friday and the mid-80s on Saturday. These highs are 15 to 25 degrees above normal in a part of the nation where many lack air conditioning in their homes and businesses, although the heat was not as brutal as in late June when Portland had a record 116 degrees and Seattle climbed to 108.

The weather has been a constant topic of conversation in the United States this month as skyrocketing temperatures plagued the Pacific Northwest, wildfire smoke covered much of Montana and Idaho in an unhealthy haze that migrated as far as New York City, severe droughts plagued California, Oregon and Washington, and monsoonal rains pounded Nevada and others parts of the Southwest.

For many residents of western states, daily life is changing to adjust to heat waves and wildfires, and there’s a growing concern that this is the new normal.

“It’s dusty and cloudy. It’s kind of like a scary movie,” said Antonio Felipe Asuncion, owner of Mixteca PDX, a Mexican restaurant in Portland. “Since the heat wave a couple weeks ago, I think it’s going to be a regular [occurrence].”

Scientists and Biden administration officials say these extremes are driven largely by climate change and are likely to become more and more common in the years to come. Oregon Gov. Kate Brown has called for swift and substantial action from Congress as climate change is “playing out before our eyes.”

“We are feeling the impacts of climate change in real time here in Oregon. Historic fires, extensive drought, unprecedented heat — we need bold action from Congress to complement the steps we’re taking at the state level,” Gov. Brown tweeted this week.

In Portland on Friday, restaurants were largely empty, kids’ summer camps ended early, and there was an ongoing rush to get air conditioning units installed. Some of the city’s suburbs did hit the 100-degree mark, according to the National Weather Service.

“It’s dead, there’s nobody here,” said Asuncion, who has owned a Mexican restaurant in Portland since 2013. “Usually we have a busy lunch and people eating outside. Today nobody is sitting outside. It’s too hot.”

Asuncion sent some workers home because business was really slow. On Thursday, the restaurant brought in only about 40 percent of usual sales as few people ventured out at all. It was another blow to his and other restaurants that are just beginning to recover from the coronavirus downturn. Now they face another extreme event they have no influence on from the unprecedented heat.

Emily Robinson is among the many in Oregon who installed an air conditioning unit this summer after years of going without.

“I don’t remember using A.C. in the past. Now I have two units in my house,” said Robinson, 41.

Robinson owns a dog walking and boarding business in Portland called Sit Clover Sit. She has also been impacted heavily by the heat with clients canceling walks and services because it’s unsafe for pets and humans to be outside. She is trying to do more walks early and late in the day and alter the routes she takes.

“This year is much more noticeable than in the past years. I’ve never had to cancel walks for heat before,” said Robinson. “Paws can’t handle a really hot pavement.”

The Oregon Humane Society has been tweeting out tips to keep animals cool this summer and reminders not to leave pets in the car while running errands. Fisherman in the Pacific Northwest and California have shared harrowing tales of finding dead salmon, clams and other marine wildlife that could not survive such warm water conditions.

As temperatures climbed this week, the Portland City Council banned homeless encampments in parts of the city that are at high risk for wildfires. The move is meant to keep people safe, but it is one more way that daily life in a place that used to be famous for moderate summers is changing rapidly.

Derrick Bradley, policy director for City Commissioner Jo Ann Hardesty, described it as “an increasingly dangerous situation as climate change effects take hold.”

Recent studies have highlighted how communities of color and low-income neighborhoods are often much warmer than high-income neighborhoods because there aren’t as many trees and green spaces in poorer areas of town.

Camp directors are also scrambling to ensure kids stay safe from both the heat and covid-19.

Jason Frazier is president of Skyhawk Sports Academy, a franchise sports camp with multiple locations in Portland and in 37 other states. He’s had to cut some camps to half-day and try to move as many activities indoors as possible to ensure kids are not outside at midday.

“The priority is the safety of the kids. If we can get kids to an indoor location and get them out of the heat, we’re going do that,” Frazier said. “We’re very careful; we slow the pace of physical activity in the afternoon, mandatory breaks in the shade. It’s a much slower pace.”

The academy also enforces mandatory water breaks and teaches coaches to look for signs of overheating. Frazier believes this is a “new normal” and that campers and coaches will have to adjust to ongoing wildfire smoke disrupting sports and outdoor activities.

“This what our summers are going to be like moving forward. We have to adapt,” Frazier said. “Whether that’s more indoors now, which is tough because of covid, or having more balanced programs throughout the year, not just in the summer.”

Long reported from Washington.