90-degree weather hitting Puget Sound after breaking record for warmest low temps in August
Aug 11, 2025, 8:08 AM | Updated: 9:56 am
Boats and other boating equipment flood Lake Union in Seattle during a summer day. (Photo: Frank Sumrall, MyNorthwest)
(Photo: Frank Sumrall, MyNorthwest)
A heat advisory warning was issued for western Washington, effective through Tuesday night at 10 p.m., due to high temperatures.
Monday’s highs will reach the upper 80s, with some areas hitting the low to mid-90s. Seattle could reach a high of 91 degrees Monday, according to the National Weather Service (NWS), alongside Tacoma and Bremerton. Temperatures in the low to mid-90s are expected in areas around Olympia and Chehalis. Everett and Bellingham will peak in the upper-80s.
The coast and sections of north Island County into San Juan County were excluded from the heat advisory.
The heat will be even more intense due to the current humidity. NWS reported the Puget Sound region has approximately 79% humidity on Monday and Tuesday.
“Even with those hot temps today, we will more than likely not set records today,” KIRO 7 meteorologist Nick Allard said. “Most records are just too high for us today.”
For reference, the record high temperatures in Seattle on Aug. 11 and 12 were 96 degrees. Olympia’s record of 96 degrees on Aug. 12 has the closest chance of being broken during this brief heatwave.
One record was broken however. Sunday night, the Seattle-Tacoma International Airport recorded the warmest low temperature for Aug. 10 in history, as temperatures never dipped below 69 degrees. The previous warmest low for Aug. 10 in the Puget Sound region was 66 degrees in 1981.
NWS is emphasizing people to take precautions for themselves by limiting time in the heat, but also for local fire crews. Fire and brush fire risks are currently heightened with these hot, dry conditions.
“The cooler ocean air will come inland Tuesday night with widespread low clouds on Wednesday morning,” Allard added. “Our highs will drop a ton with temps only in the low to mid-70s with some afternoon sun.”
By Wednesday, highs are expected to only reach the mid-70s for the next seven days. In typical fashion, rain is expected to follow this two-day heat spell. Showers are on schedule for Friday through Saturday, with highs peaking in the upper 60s only.
Contributing: Gwen Baumgartner, KIRO Newsradio; KIRO 7
