Joe Duhownik

PHOENIX (CN) — Arizona’s capital city experienced higher average temperatures last month than in any other June on record, but experts say that may mean a cooler, wetter July.

The average temperature in Phoenix hovered at 97 degrees Fahrenheit from June 1 to June 30, the National Weather Service announced Monday morning. June 2023 saw an average of only 90 degrees. This June’s average beat the city’s previous record of 95.3 degrees set in 2021.

But high temperatures this June barely eclipsed those of last June. Instead, what made this June so much hotter was a lack of cooling at night.

“The average minimum temperature change was three times greater than the average maximum temperature change,” Arizona climatologist Erin Saffel said in a phone interview.

Saffel said the main reason for persistent heat through the evenings is an effect called the “urban heat island.” Over grass or other natural landscapes, sunlight heats the ground and in turn heats the air above it. But the cement, asphalt and metal that make up the Phoenix metropolitan area instead absorb the heat and hold until nightfall, when it then slowly releases the heat into the air, maintaining higher temperatures until the sun rises again to restart the process.

Saffel said this phenomenon has only worsened as the area has been further developed over the last few decades.

While the heat is already overwhelming — Maricopa County has confirmed six heat-related deaths this year and is investigating 11 others — a hotter June may mean more moisture and therefore more rainfall for the rest of the summer.

Monsoon season in Arizona spans June 15 to Sept. 30 when shifting wind patterns bring humidity from the Gulf of California and other tropical regions, adding enough moisture to the air to trigger thunderstorms and heavy rain.

The summer heat creates a high-pressure ridge of hot, dry air over Arizona and the Four Corners region, which sits in place until the monsoon winds are strong enough to push it out of the way and replace it with humidity and thunderstorms.

National Weather Service meteorologist Ryan Worley said warm June air can help pull more moisture into the region.

“Normally, that can correlate to a fairly active monsoon,” he said in a phone interview.

Heavy rains typically begin to fall in early July, but most Phoenix metro citizens had to wait until August to see significant rainfall this past summer. The city went four complete months without measurable rainfall, which had never happened before, Saffel said

Phoenix has already received rainfall — albeit only scattered showers — in both June and July. But Saffel said more significant storms may reach the city as soon as next week.

“An early start to our monsoon could be that we might have the potential for more storms,” Saffel said. “Or it could be that everything bombs out. But statistically, there’s a better chance of more storms.”

Not only was last summer one of the driest on record, but July 2023 marked the hottest single month any city has experienced in U.S. history. The average temperature in Phoenix last June was 112.7 degrees. Temperatures rose to 115 degrees or higher on 17 days and hit 119 degrees three times, breaking records nearly daily.

This July isn’t expected to be quite as hot, Worley said.

“We’re definitely gonna start off hotter than normal,” Worley told Courthouse News. “It’s a little harder to tell what we’re gonna see beyond that.”

Tuesday’s high is 112 degrees, and by Friday that could climb as high as 116 degrees in Phoenix and 115 degrees in Yuma. Just across the Colorado river, the town of El Centro, California, could reach 117 degrees.

Maricopa, Yuma and La Paz Counties, as well as part of Pinal County, are under excessive heat watch for the next seven days.

Heat is the deadliest weather element in Arizona, according to the National Weather Service. Between 2010 and 2020, the Grand Canyon State saw more than 3,000 heat-related deaths. Maricopa County recorded 425 heat-related deaths in 2022.

To prevent heat-related illness, the weather service recommends avoiding being outdoors. If necessary, drink one or two liters of water for every hour spent outside, and limit strenuous activity to the early mornings and late evenings. If a person becomes confused, dizzy or unconscious in the heat, call 911 immediately. The Maricopa County health department maintains a heat-relief map including cooling stations, hydration stations and donation sites for those who can’t escape the extreme heat.