Unprecedented stretch of fall heat expected to shatter records in Phoenix

PHOENIX — The seasons may have changed, but the summer heat isn’t easing its searing grip on the Valley.

Phoenix temperature records are expected to fall like leaves this week due to an unprecedented autumn heat wave.

Temps will continue to heat up across the region, with record-breaking temps in the forecast as highs are expected to approach or exceed 110° through the remainder of this week. An Excessive Heat Warning goes into effect today for much of south-central AZ. #azwx #cawx pic.twitter.com/T12SWbYaTW

— NWS Phoenix (@NWSPhoenix) September 25, 2024

“We do have a strong area of high pressure that’s going to be sitting right over the western United States. That’s really going to be helping boost these temperatures for us well above normal,” Isaac Smith, a meteorologist for the National Weather Service in Phoenix, told KTAR News 92.3 FM on Wednesday morning.

Phoenix Sky Harbor International Airport, which the NWS uses for the city’s official readings, tied a record for the date on Tuesday by hitting 108 degrees, but that was just a warmup.

On Wednesday, Phoenix topped its 35-year-old record for the date, which had been 108 degrees.

The forecast calls for highs of at least 110 degrees Wednesday through Sunday, with new Phoenix temperature records expected each day at least through Tuesday.

“We’re going to be looking at these temperatures … just absolutely the shattering these records in some cases,” Smith said.

Saturday is expected to be the hottest of the upcoming hot days, with a forecast high of 113 degrees, a whopping 5 degrees above the existing record for the date.

Arizona’s most populous city has never seen this kind of heat this deep into a year. Until now, the latest date with a high of 110 degrees in Phoenix was Sept. 19 in 2010.

The highs in Phoenix are normally 96-97 degrees this time of year.

Excessive heat warning issued for low desert areas

To alert the public, the NWS is activating an excessive heat warning for the low deserts of central and southwestern Arizona. The warning is scheduled to run from 10 a.m. Wednesday to 8 p.m. Sunday.

Per city of Phoenix policy, the Echo Canyon and Cholla trails at Camelback Mountain and all Piestewa Peak trails are closed from 9 a.m. to 5 a.m. on days when excessive heat warnings are in effect.

“When we see temperatures like this, it is very important to stay cool and to stay hydrated,” Smith said. “You definitely need to be eliminating your time outdoors. If you have any activities you need to be doing outside, be doing that early in the morning before we start seeing this heat really ramp up.”

Phoenix temperature records keep coming

Phoenix temperature records are nothing new in 2024. The city already set a standard for most days of at least 110 degrees in a year at 61 and counting. The old mark was 55 days in 2023.

Phoenix also endured a record-shattering 113-day streak of temperatures reaching triple digits, which finally ended last week.

And if that’s not enough, Phoenix’s 2024 “meteorological summer” (June-August) was the hottest on record, with an average temperature of 98.9 degrees.

It might not just be the daily highs that add to the record list this week, Smith said.

“We’re going to be looking at overnight lows in the upper 70s to low 80s, so we’ll maybe looking at some record warm lows as well,” he said.

KTAR News 92.3 FM’s Jim Cross contributed to this report.

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