Record heat wave: Phoenix breaks mark for longest streak of 110-degree days

PHOENIX — The ongoing and relentless Phoenix heat wave singed another mark into the record books Tuesday, when it reached 110 degrees for the 19th consecutive day.

The 110 mark was hit at 11:59 a.m., according to the National Weather Service. The temperature eventually soared to 118 degrees, shattering the record for the date. The previous high for July 18 was 115 in 1989.

The city’s previous longest streak of 110-plus days was 18, set in June 1974. The mark was tied Monday when it hit 116 degrees, which matched the daily record for July 17 set in 2005.

Record Broken: As of 11:59 AM MST, Phoenix Sky Harbor Airport has reached 110°F. This is now the 19th straight day with a temperature that reaches or exceeds 110°F, which breaks the previous record of 18 days set back in 1974, nearly 50 years ago. #azwx pic.twitter.com/nBJaY8fN6z

— NWS Phoenix (@NWSPhoenix) July 18, 2023

“We’ll continue to see those temperatures add up,” meteorologist Isaac Smith of the National Weather Service in Phoenix told KTAR News 92.3 FM on Tuesday morning.

How long will Phoenix’s 110-degree temperatures last?

The current hot streak, which is based on daily high temperatures recorded at Phoenix Sky Harbor International Airport, started June 30.

According to weather historian Christopher Burt of the Weather Company, no other major U.S. city has seen a longer stretch of days reaching at least 110 degrees.

Phoenix’s streak is expected to continue at least through Sunday, according to the National Weather Service’s seven-day forecast.

“Going through the rest of the week, we’re not really going to be looking at much in terms of relief from the heat,” Smith said. “So, we’re going to be looking at temperatures pretty much staying at or above 115 through much of the week.”

Other record extreme heat streaks continue

While Phoenix temperatures continue to soar while the sun is out, there hasn’t been much relief overnight.

The morning low Tuesday was 94 degrees, a record warm low for July 18.

That extended Phoenix’s record streak of daily lows at or above 90 to nine consecutive days. The previous mark of seven days was seen twice in 2020 and once in 2012.

The low this morning in Phoenix was 94°F. This breaks the record warm low for the date and is the 9th consecutive day with a low temperature at or above 90°F. #azwx pic.twitter.com/l0azmr0cQv

— NWS Phoenix (@NWSPhoenix) July 18, 2023

A record-long excessive heat warning for the Valley started July 1 and has been extended multiple times. As of Tuesday, the 18th day of the warning, it was set to run through Friday, but it could be extended again.

The National Weather Service has been issuing excessive heat warnings since 2006 as a way to alert communities about potentially dangerous heat. They are based on several parameters, not just temperatures. Until now, the Valley’s longest excessive heat warning ran for 10 days in June 2017.

What is causing Valley’s record heat wave

Since 1983, Phoenix’s average daily summer temperature has increased 3.6 degrees, its daily high temperature has gone up 3.2 degrees and its nighttime low has gone up 4.4 degrees, according to the National Oceanic and Atmospheric Administration.

The current heat wave has both long and short-term causes, said Arizona State University’s Randy Cerveny, who coordinates weather record verification for the World Meteorological Organization.

“The long-term is the continuation of increasing temperatures in recent decades due to human influence on climate, while the short-term cause is the persistence over the last few weeks of a very strong upper-level ridge of high pressure over the western United States,” Cerveny told The Associated Press.

The heat wave is “a harbinger of things to come given that the most reliable projected impacts of climate change are those that are directly related to the increase in global temperatures,” said Katharine Jacobs, director of the Center for Climate Adaptation Science and Solutions at the University of Arizona.

How to beat Arizona heat

Too much time in the Arizona sun can lead to heat exhaustion, heat stroke and death.

Warning signs of heat-related illnesses can include heavy sweating, muscle cramps, weakness, headache and nausea.

Outdoor activities should be curtailed between sunrise and sunset during periods of excessive heat. People should also drink more water than usual and avoid sugary, caffeinated drinks, which dehydrate the body.

Per a city of Phoenix policy implemented to protect hikers and rescue crews, Camelback Mountain’s Echo Canyon and Cholla trails and all Piestewa Peak trails are closed from 11 a.m. to 5 p.m. on days with excessive heat warnings.

Dangerous heat will continue through the remainder of the work week. Make sure you are prepared and ask yourself these questions if spending longer periods of time outdoors. #azwx pic.twitter.com/hbzqRRMt4t

— NWS Phoenix (@NWSPhoenix) July 18, 2023

Dogs aren’t allowed on Phoenix trails when the temperature is in triple digits.

Planning agency Maricopa Association of Governments operates the regional Heat Relief Network annually from May 1 to Sept. 30. The program includes an interactive online map showing the location of more than 200 cooling centers, respite centers, hydration stations and collection sites.

KTAR News 92.3 FM’s Jim Cross and The Associated Press contributed to this report.

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