Fun's fun, summer's great and all that. But Henry Severson, 4, seems to have had his fill of triple digits at this point, and summer's only just begun. Henry was trying to stay cool Tuesday at the Oro Valley Aquatic Center, 23 W. Calle Concordia.


Tucson is poised to sizzle its way to a heat record: a month in which every single day tops out at 100 degrees or higher. 

"It's almost certain that every day in June will be 100 degrees or above," said Jim Meyer, a meteorologist with the National Weather Service. "We have never had a month like that before - when every day reached 100 degrees or above."

The previous record for triple-digit days in a month was 28 - set last June. After Tucson hit 102 on Wednesday, according to the National Weather Service, only four more days remain to eclipse the record.

Meyer said forecasts call for highs of at least 100 every day through Tuesday - with temperatures soaring to 110 or 111 scorching degrees on Friday, Saturday and Sunday.

"Next Wednesday is the first vulnerable day for not being over 100," Meyer said. "By then, we might see a bit of moisture coming in from the south and southeast. Right now, we expect it to knock the temperatures down to 101 or 102. But if we're lucky and get a little more moisture than we're expecting, it could drop into the high 90s" for a daily high.

Meyer said an excessive-heat watch is in effect for Friday, Saturday and Sunday before a gradual cooling next week.


Natural variability of temperatures and a warming climate are among possible causes of our run of triple-digit days, said a University of Arizona climate scientist.

"I think there are a few things at play," said Zack Guido, associate staff scientist with Climate Assessment for the Southwest at the UA. "Historically, this is the hottest and driest time of the year, and there is some natural variability that in any one year could cause there to be a higher number of 100-degree days than the next year."

Another factor, Guido said, is that "it's getting warmer."

"It's on the order of 1 to 2 degrees Fahrenheit that the temperature is going up over the last 40 years," he said. "That's for the West overall. It could be even higher here" in the Southwest.

Guido said it's not certain whether those warming temperatures and this month's many 100-degree days are tied to human activity.

"Whether or not this full month of 100-degree temperatures is an expression of anthropogenic (human-caused) climate change, I don't know," he said. "But it does fit with the narrative of temperatures increasing."

Did you know?

39 days The record for consecutive days in which temperatures reached 100 degrees or higher in Tucson is 39. The 39-day period in 2005 extended from June 14 through July 22.

99 days The Tucson record for the most days of 100 degrees or higher in a year is 99 days - set in 1994.

Source: National Weather Service

Surviving the heat


  • Stay indoors when possible.
  • Restrict activities to early morning or evening.
  • Wear loose-fitting, light-colored clothing.
  • Drink plenty of water, take breaks.
  • Check on the elderly and those with health conditions.
  • Don't leave children or pets in vehicles.
  • • Recognize symptoms of heat-related illnesses and seek medical attention.


Dizziness, headache, sweaty skin or red, hot, dry skin; cramping, nausea and vomiting; rapid heartbeat; confusion; convulsions and fainting.

It could be worse

The high Saturday in Phoenix is expected to be 118.

Contact reporter Doug Kreutz at or at 573-4192. On Twitter: @DouglasKreutz