RENO, Nevada — The first heat wave of the year maintained its grip on the US Southwest on Friday, a day after records tumbled across the region as temperatures soared past 110 degrees Fahrenheit (43 degrees Celsius) from California to Arizona.

Although the official start of summer is still two weeks away, roughly half of Arizona and Nevada were under an excessive heat alert, which the National Weather Service extended until Friday evening. The alert was extended through Saturday in Las Vegas, where it's never been hotter this early in the year.