Phoenix heat wave may be the longest ever and temperatures will likely increase

July 11, 2023

The excessive heat warning that hit Phoenix on June 30 is likely to continue into next week and become the longest heat wave on record, according to the National Weather Service. A recent study predicted half of Phoenix residents would need emergency medical attention if a multiday blackout were to coincide with a heat wave. Temperatures are likely to increase throughout this week as the heat dome intensifies. Instead, the moisture will actually increase overnight temperatures and keep low temperatures in the 90s, he said. What's next: NWS extended the excessive heat warning through Sunday, but Lojero says it could persist even longer.