The longest stretch of triple-digit days in Phoenix history has come to an end after a record-shattering 113 days. Tuesday was the first day since May 27 that stayed below 100 degrees at Phoenix Sky Harbor International Airport.
“We just happened to see a very strong area of high pressure sit almost directly over the state for most of the summer,” National Weather Service meteorologist Mark O’Malley told KJZZ News. “Typically during the monsoon, that area of high pressure will weaken and shift around, however this year, it did not budge.”
The previous record for the longest continuous stretch of triple-digit high temperatures was 76 days, set in 1993.
The relentless heat of the past few months made 2024 Phoenix’s hottest summer ever, O’Malley said.
“But it wasn’t just Phoenix,” O’Malley said. “The entire state — this was the warmest summer that Arizona has ever seen in the period of record, and this goes back over 125 years.”
In addition to the months-long stretch of 100-degree temperatures, Phoenix broke several other heat records this summer. The city has also seen a record number of days with highs above 110 this year and a record number of nights with lows in the 90s.
“This is pretty much an unprecedented situation that we saw this summer,” said Randy Cerveny, an Arizona State University geographical sciences professor and rapporteur on extreme records for the World Meteorological Organization.
Cerveny said the previous records for most 110-degree days and 90-degree nights had been set just last year. The fact that those records keep falling points to a clear climate change-driven trend, he said.
“We’re seeing something that’s fundamentally changing about our climate system,” Cerveny said. “We’re having hotter summers, and particularly hotter summers in terms of minimum temperatures, and those kinds of things are the direct result of greenhouse gasses in our atmosphere.”
Storm systems in the northern part of the state are pushing cooler air toward Phoenix, so O’Malley expects highs will stay below 100 for the rest of this week. But he said Phoenix is not done with hot weather yet for 2024.
“It does look like 100-degree temperatures will return next week, and that is not unusual for this time of year,” O’Malley said.
Phoenix typically does not see its last 100-degree day of the year until the first week of October.
