Hot desert nights. New daily record set for Tri-Cities overnight warmth

The longest extreme heat watch of the summer has ended for the Tri-Cities, although more triple-digit temperatures are expected in September.

But it was not the high temperatures that were an issue in the last several days of hot weather — it was the low temperatures.

Tuesday set a new daily record for the warmest night on record for Aug. 26 in the Tri-Cities, according to the National Weather Service.

The low temperature was 66, which was a degree above the record warm nighttime temperature for that date, 65, recorded in 1956.

If the overnight temperature does not drop low enough, people are unable to cool down and recover from the daytime heat, according to Environmental Health Perspectives.

In contrast, the high Tuesday reached only 92, a full 10 degrees below the record high of 102 set in 1938.

Sunday was the only day during the recent extreme heat watch for the Tri-Cities with triple digit temperatures at a high of 101.

It likely will not be the last triple-digit temperature of 2025.

Wednesday also will be cooler with a high of 88 forecast, although the overnight low could still be unseasonably warm at a forecast 69 degrees, according to the National Weather Service.

Overnight lows should remain unseasonably warm in the mid 60s to 70 through Wednesday night, according to the weather service. Normal lows for late August are more than 10 degrees cooler at 52 to 53 degrees.

Highs should be back in the 90s Thursday through Labor Day weekend, then warm to triple digits from Tuesday through Thursday, according to the weather service.

This story was originally published August 27, 2025 at 10:48 AM.