It was the 54th day this year that the official reading at Phoenix Sky Harbor Airport made the mark, eclipsing the previous record of 53 days set in 2020.
Matt Salerno, a National Weather Service meteorologist, said the hot streak could reach 55 days.
“We do have one more day,” he said.
An extreme heat warning remained in effect, with temperatures forecast at 43.9 C on Sunday and 41.1 C on Monday.
Salerno said Phoenix experienced the hottest three months since record-keeping began in 1895, including the hottest July and the second-hottest August.
The daily average temperature of 36.1 C in June, July and August passed the previous record of 35.9 C set three years ago.
The average daily temperature was 39.3 C in July, Salerno said, and the daily average in August was 37.1 C.
In July, Phoenix also set a record with a 31-day streak of highs at or above 43.3 C. The previous record of 18 straight days was set in 1974.
The sweltering summer of 2023 has seen a historic heat wave stretching from Texas across New Mexico and Arizona and into California’s desert.
Worldwide, last month was the hottest August ever recorded, according to the World Meteorological Organization. It was also the second hottest month measured, behind only July 2023. Scientists blame human-caused climate change with an extra push from a natural El Nino, which is a temporary warming of parts of the Pacific Ocean that changes weather around the globe.
As of Saturday, Phoenix has tallied 104 days this year with temperatures over 37.7 C, Salerno said. That’s in line with the average of 111 days of 37.7 C or higher every year between 1991 and 2020.
Maricopa County, home to Phoenix and the most populous county in Arizona, also appears headed toward an annual record for heat-associated deaths.
County public health officials have confirmed 194 heat-associated deaths this year as of Sept. 2. An additional 351 cases are under investigation.
Maricopa County confirmed 425 heat-related deaths in 2022.