The temperature hit a record high 91 on Wednesday at Portland. The Weather Service says that broke the old record of 88 for the date set in 2012.
A record of 88 was set at Newport, breaking the old record of 78 set in 1912. And, a record of 87 was set at Astoria, breaking the old record of 82 set in 1939.
Temperatures around 80 were recorded in the Seattle area.
Forecasters say Thursday will be the last day of Northwest heat.
The Weather Service says cooler marine air will move inland Thursday night and Friday into Oregon and Washington bringing a chance of weekend showers and unsettled weather into next week.