The air quality in Seattle was among the worst in the world Monday, ranking 10th, according to one online air quality database.

That’s thanks to mostly stagnant air allowing smoke from the Bolt Creek wildfire to “settle” in King and Snohomish Counties, said Maddie Kristell, meteorologist for the National Weather Service’s Seattle office. 

The human-caused Bolt Creek wildfire that started early Sept. 10 is now at about 12,486 acres. As of Monday evening it was about 36% contained

Without a lot of wind, an overnight “downslope flow” carries smoke off the Cascades south toward Seattle, said Matthew Dehr, lead meteorologist for the state Department of Natural Resources. 

The smoke should be on its way out by Wednesday or Thursday, Kristell said, when an “onshore flow” is expected to treat the region to some marine air. 

Meanwhile, in and around the Cascades, the smoke will hang out all week, Dehr said. Areas near Lake Wenatchee to Leavenworth will have air quality in the unhealthy to hazardous range for the next week or so.


People who have heart disease, or lung diseases like chronic obstructive pulmonary disease or asthma; children; and pregnant people are more likely to be affected by health threats from smoke, according to the U.S. Centers for Disease Control and Prevention.

The CDC recommends people keep windows and doors closed and run an air conditioner to keep indoor spaces smoke free, if possible. In Washington state, people can keep tabs on current and future air quality using the state Department of Ecology’s Smoke Forecast.

The Bolt Creek wildfire continues to burn “pretty actively” because of a combination of unseasonably warm September temperatures and a prolonged dry period, Dehr said. 

Seattle has had a record warm start to October, with three consecutive days over 75 degrees.

Seattle has seen only 0.48 inches of rain from July to September, versus an average 3.16 inches, making it the driest that stretch has been on record, Dehr said.

“The make-or-break point right now,” he said, “for whether we’re going to head into a drought or whether we’re going to get back more to normal is how our October goes.”