Weekend forecast calls for drop in temperatures, possible widespread thunderstorms

Goodbye sweltering temperatures, hello thunderstorms.

The Phoenix area’s extreme heat warning finally ends this weekend and will give way to increased monsoon activity.

The forecast calls for highs of at least 110 degrees Friday and Saturday, the last day of an extreme heat warning that started Aug. 17.

“But then we’re going to start to see a pattern shift … starting on Sunday and into next week where temperatures are actually going to be much cooler, with highs right around in the lower to mid-100s, so right around average for this time of the year,” meteorologist Gabriel Lojero of the National Weather Service in Phoenix told KTAR News 92.3 FM on Friday morning.

When is the best chance for Thunderstorms around Phoenix?

Additionally, the possibility of storms will increase through the weekend, with the best chances for widespread activity Sunday and Monday. The monsoon could flare up earlier if the conditions are right, Lojero said.

“But the problem with tomorrow [Saturday] is that everything is going to be conditional of strong or even colliding outflow boundaries producing new storm activity for tomorrow evening,” he said.

The instability needed to generate widespread thunderstorms is more likely Sunday and Monday.

“And with these thunderstorms, there’s a potential for strong to severe wind gusts as well as blowing dust and … flash flooding if you get a lot of heavy rain in a short amount of time,” Lojero said. “So, a more active, potentially more impactful period [is] coming up.”

How to stay safe during extreme heat warnings

Extreme heat warnings trigger daytime closures of hiking trails at Camelback Mountain, Piestewa Peak and South Mountain in Phoenix.

The danger is real. The Maricopa County Public Health Department has confirmed 113 heat-related deaths so far this year, more than triple the number at this time in 2025.

Health experts urge precautions during times of extreme heat, such as keeping hydrated, wearing light clothing and remaining indoors with air conditioning during the hottest times of the day.

The Maricopa County Heat Relief Network offers free, cool spaces and other resources to people who need relief from the heat from May to September.

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