Record-warm nights set in U.S. southwest heatwave

 Record-warm overnight temperatures were reported in parts of the U.S. Southwest on Friday as an extreme heat warning remained in effect across parts of California, Nevada and Arizona, according to the U.S. National Weather Service (NWS).

The temperature at Death Valley, California, was no lower than 38.3 degrees Celsius on Friday, breaking the previous Aug. 21 record of 37.8 degrees Celsius set in 1919, according to the NWS Las Vegas office.

At Desert Rock-Mercury, Nevada, the low temperature held at 28.9 degrees Celsius, tying the Aug. 21 record set in 2018, the office said.

The weather service refers to such measurements as record high minimum temperatures, which measure the warmest daily low rather than the highest afternoon temperature.

The office said the warning covered Death Valley National Park, the Las Vegas Valley, Lake Mead, Lake Mohave and the Lower Colorado River Valley. The warning was in effect through Sunday evening.

The NWS San Diego office said above-average high and low temperatures would continue through next week. It said unusually warm nights would limit relief from the heat in some areas.