‘Extreme heat watch’ for Tri-Cities, parts of PNW may be longest of summer
Summer may be winding down, but what’s forecast to be the longest heat wave of 2025 is still ahead for the Tri-Cities.
The National Weather Service has issued an extreme heat watch for the Tri-Cities area starting Saturday, the busiest day of the Benton Franklin Fair, and continuing through at least Tuesday, the first day of school for most kids in Richland and Pasco. Kennewick classes in most schools begin Wednesday.
The Tri-Cities has had just nine days when the temperature reached 100 or hotter this summer. The longest stretch was three days of 101 to 102 highs starting Aug. 13. The highest temperature this year was 104.
Now the weather service shows a possibility of four days of 100 or 100-plus highs starting this weekend.
The weather service forecast calls for a high of 100 on Saturday, 100 on Monday and 101 on Tuesday. Sunday may or may not hit 100.
The weather service forecasts a high of 98 for Sunday. That is the center of a range of a few degrees it believes most likely, making 100 a possibility Sunday.
The weather service has not extended the extreme heat watch past Tuesday, but Wednesday also is expected to be hot with a high forecast now at 99.
The Weather Channel, which releases a 10-day forecast, predicts that the high will drop to 94 on Thursday, Aug. 28, with highs in the mid to low 90s then through the end of August.
The risk for heat-related illnesses for Saturday to Tuesday is rated as “major” by the weather service.
Those without air-conditioning will get little relief at night to cool their bodies down before another hot day starts. Fans and open windows will not be enough, according to the weather service.
Overnight lows will warm from 61 forecast for Friday night to 67 Saturday night and then 69 to 70 for Sunday through Tuesday nights, according to the weather service.
The weather service recommends drinking plenty of water, wearing lightweight and light-colored clothing, and scheduling outdoor activities before 10 a.m. or after 4 p.m.
This story was originally published August 21, 2025 at 11:14 AM.