Seattle's AQI reaches moderate levels as wildfire smoke accumulates

SEATTLE – While Western Washington will experience unseasonably hot weather this weekend, air quality across the region will deteriorate slightly.

Seattle's air quality index (AQI) rose from good to moderate on Thursday, and that level is expected to remain that way through Monday, according to IQ Air forecasts. Moderate air quality, which is a reading between 51 and 100 on the AQI, means some people in sensitive groups should be cautious about outdoor activities.

The AQI in Seattle was 58 at 7:30 a.m. Friday morning, according to IQ Air. That number is expected to rise to 66 on Saturday and 73 on Sunday.

IQ Air's live air quality forecast shows that air quality is mostly good in the area north of Everett on the Washington state coast. South of Tacoma and Olympia, more stations are reporting AQI levels above 100. Ashley Ruiz, meteorologist at KING 5, says most of the smoke should remain in the air in the Seattle area.

Thursday's unseasonable heat led to some daily temperature records across the region, including in Seattle, SeaTac, Olympia and Quillayute. Temperatures will be back at 90 degrees or above across the region on Friday. A heat advisory is in effect for much of Western Washington until 11 p.m. This means there is a moderate risk of heat-related illness, especially for people who don't have access to effective cooling or adequate hydration.

The National Weather Service (NWS) has issued an air quality warning for Lewis County until noon Saturday due to wildfire smoke. “All sensitive groups should limit time spent outdoors. People with underlying health conditions may experience worsening symptoms. Healthy people may experience symptoms,” the NWS wrote in its warning.