Phoenix forecast calls for more extreme heat followed by chance for rain

PHOENIX – The ongoing extreme heat warning for metro Phoenix has been extended by another day, but that’s not the biggest weather news of the week.

The real headline-grabbing development is the potential for rain.

“We’re looking at an increase in moisture across south-central Arizona later this week,” Mark O’Malley of the National Weather Service (NWS) in Phoenix told KTAR News 92.3 FM on Tuesday morning.

“We’ll first look at some gusty winds coming into the area. But by Thursday-Friday, there’s a better chance of rainfall in the metro, between a 30 and 50% chance.”

However, O’Malley cautioned that the rain isn’t expected to blanket the Valley.

“But, hopefully a few lucky areas will see a little bit of relief,” he said.

Rain chances will increase later this week and expand into the lower deserts. The best chances will fall on Thursday and Friday. Moisture levels will still be fairly limited, so rainfall amounts should be on the light side for most locations. #azwx #cawx pic.twitter.com/59P6knhE90

— NWS Phoenix (@NWSPhoenix) August 12, 2025

When was the last time it rained in Phoenix?

It hasn’t rained at Phoenix Sky Harbor International Airport, which the NWS uses for the city’s official readings, since 0.16 inches fell on July 2. That also was Phoenix’s only measurable rainfall since the official start of the monsoon season on June 15.

“So far this monsoon, it’s been fairly dry across south-central Arizona. … We still have a month-and-a-half to go here, so we still have time to make up the difference,” O’Malley said.

Arizona’s monsoon season runs through Sept. 30 each year.

In addition to bringing moisture to the Valley, the weather system is expected to drop daily highs to the normal range of 105 degrees for this time of year – and possibly lower.

“We are looking for some cooler weather entering the Phoenix metro later this week,” O’Malley said. “By the weekend, high temperatures in the metro only will be between about 100 and 105 degrees.”

Why was extreme heat warning extended in Phoenix?

But first, the Valley will have at least two more days under an extreme heat warning.

The advisory originally went into effect Aug. 1 and has been extended multiple times. Late last week, the NWS extended it through 8 p.m. Tuesday. But another day was added due to persistent extreme heat.

The Extreme Heat Warning for portions of south-central and southwest AZ and southeast CA has been extended through Wednesday evening. Expect highs temperatures mostly between 109-113° for today and Wednesday. Near normal temperatures are forecast by Friday. #azwx #cawx pic.twitter.com/lWtGLD56My

— NWS Phoenix (@NWSPhoenix) August 12, 2025

“We’re looking at temperatures in the Phoenix metro area around 110 over the next couple of days. So, the excessive heat warning has been extended through Wednesday,” O’Malley said.

Three Phoenix daily heat records have fallen since the extreme heat warning started. Furthermore, Thursday was the hottest August day ever recorded in the city with a high of 118 degrees.

Due to the dangerous conditions, the following Phoenix hiking trails are restricted from 8 a.m. to 5 p.m. on extreme heat warning days:

• Camelback Mountain: Echo Canyon Trail and Cholla trail.
• Phoenix Mountains Preserve: Piestewa Peak Summit Trail and associated trails.
• South Mountain Park and Preserve: Holbert Trail, Mormon Trail, Hau’Pal Loop Trail and access to the National Trail from the Pima Canyon Trailhead.

KTAR News 92.3 FM’s Kellen Shover contributed to this report.

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