Phoenix sets record of 31 straight days of 110-degree temps

On Monday, Phoenix finally stopped adding new notches to its record of consecutive days with heat of 110 degrees Fahrenheit or higher, but more hot days are just around the corner.

The high temperature at Phoenix Sky Harbor Airport reached 108 degrees on Monday, according to a social media post from the National Weather Service in Phoenix.

That high on Monday ended the 31-day record of consecutive days of high temperatures of 110 degrees Fahrenheit or higher.

The 31-day streak blew past the previous record of 18 consecutive days set in 1974, according to the NWS

While the reprieve was desperately welcome, temperatures are due to start climbing again on Wednesday, the NWS said in its Tuesday bulletin.

“Wednesday will mark the start of a warming trend with high temperatures eventually expected to once again top 110 degrees over much of the lower deserts by Friday. An Excessive Heat Watch has been issued for much of south-central Arizona from Friday through Sunday,” the National Weather Service said.

Phoenix is used to hot weather in the summer, but global warming trends have added heat, according to research from scientists at the World Weather Attribution, an organization that quantifies how much of an extreme weather event is attributable to climate change.  

“Researchers found that the Southwest heat wave in July was almost 4° Fahrenheit warmer as a result of climate change,” Erinanne M. Saffell, the Arizona State Climatologist and Director of the Arizona State Climate Office, told CNBC, referring to the research from the World Weather Attribution scientists.

The heat in Phoenix was also a result of a stubborn weather pattern called a “heat dome,” lack of rain, and what Saffell called “an extreme heat island,” where buildings, roads and the infrastructure of urban areas contribute to higher temperatures than more rural areas.

“The Phoenix urban heat island has twice the signature of the global impact. The urban heat island largely keeps night temperatures warmer,” Saffell told CNBC. “In July, night temperatures did not cool off below 90 degrees Fahrenheit on 19 days and set a new record ‘max’ minimum temperature of 97 degrees Fahrenheit. That means it didn’t cool off below 97 degrees Fahrenheit that night.”

The brutal month made July in Phoenix the hottest month on record for any US city, with an average temperature of 102.7 degrees, according to data the Arizona State Climatologist and Arizona State Climate Office shared on social media.

The previous average monthly high for Phoenix was 99.1 degrees in Aug. 2020, and the previous national high was set in Lake Havasu City, Ariz., in July 1996, when it experienced an average temp of 102.2 degrees, Saffell told CNBC.

Prolonged periods of extreme heat are dangerous. According to the most recent heat mortality report from Maricopa County, where Phoenix is located, 25 deaths from the heat have been confirmed. Another 249 deaths are still under investigation to determine if they are attributable to heat.

“The heat has been unrelenting in our community, I am so thankful to our first responders who are out there taking care of people who are vulnerable to anyone who has to work outdoors,” Phoenix mayor Kate Gallego told CBS’ Margaret Brennon on “Face the Nation” earlier in July.

Phoenix has mobile cooling units that it dispatches to emergency zones and will give patients cool IVs to cool them from the inside, Gallego said.