Thursday marks 35 years since Phoenix’s hottest day on record. On June 26, 1990, the temperature soared to 122 degrees.
Will Phoenix ever get that hot again?
“The way I look at these numbers is, once we hit that number, it means we can hit it again,” said state Climatologist Erinanne Saffell. “But I also look at the trends. So it’s been 35 years since we’ve hit it, so hopefully it’s not going to happen too much more often or frequently.”
Even though that record holds, Phoenix has seen many other types of heat records shattered in the last 35 years.
Randy Cerveny is a professor of geographical sciences at Arizona State University and rapporteur on extreme records for the World Meteorological Organization. He said overnight low temperatures are actually rising much faster than daytime highs.
“I expect a record minimum temperature of 100 degrees to be set before we get above 122, which is our record maximum temperature,” Cerveny said.
The scorching summer of 1990 had just four nights with low temperatures in the 90s. Last summer, Phoenix had a record 39 nights in the 90s.
The hottest temperature recorded last June in Phoenix was 117 – a far cry from 122. But because overnight low temperatures were so much warmer, the average temperature for the month of June 2024 was 3 degrees warmer than the monthly average temperature for June 1990.
Cerveny said nighttime warming is a result of human-caused climate change.
“Carbon dioxide traps in the heat that’s collected during the day and therefore we get hotter during the night,” Cerveny said. “It’s one of the clear indications that we have that climate change is going on.”
Climate change is also making Phoenix’s heat season much longer. In 1990, the last day above 110 degrees fell on Sep. 11. Last year, the 110s lasted until Oct. 7.
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