Record heat in the Phoenix metro area this week also led to near-record electricity use by Arizona Public Service customers.
Officials with the state's largest utility company say APS customer demand reached 7,320 megawatts on Tuesday.
That set the peak for the most electricity used at the same time so far this year.
APS's record for peak demand is 7,363 megawatts, set on June 20, 2017.
For each of the first three days this week, APS customers used about twice as much energy as they do on an average winter day.
APS serves about 2.7 million people in 11 of Arizona's 15 counties.
Already devilishly hot for being in the Sonoran desert, Arizona's largest city is also an "urban heat island," a phenomenon that pushes up temperatures in areas covered in heat-retaining asphalt and concrete. Phoenix on Wednesday recorded a sweltering 116 degrees, setting a new high for the date.
Phoenix officials say they are tackling urban warming, monitoring downtown temperatures, planting thousands of trees and capturing rainwater to cool off public spaces.