As Arizona monsoon season winds down, all eyes turn toward El Niño

As the monsoon season winds down, Arizona weather forecasters are turning their attention to El Niño.

El Niño is a climate pattern defined by warm surface temperatures in the eastern Pacific Ocean. Jonny Malloy, a meteorologist for the Maricopa County Flood Control District, said the pattern typically elevates the atmospheric moisture in the Southwest.

This season’s El Niño was declared June 11 and has been intensifying, Malloy told KTAR News 92.3 FM’s Arizona’s Morning News on Tuesday.

“We’ve already felt that during the monsoon season. … A lot of humidity’s out there, and really that’s going to extend into the fall into winter pattern,” he said. “So what does that mean for us, right? So, statistically it usually means we have a wetter pattern in play.”

El Niño contributed to last week’s storm activity

El Niño made its presence known on Wednesday, when thunderstorms triggered flash flooding while dumping more than 3 inches of rain in parts of metro Phoenix.

“Usually when you start getting this part of the season where the monsoon circulation starts breaking down, moving around a little bit more, we get more of the Pacific trough influence. So even last week, the very heavy rain we experienced, that was kind of a hybrid-type event,” Malloy said.

El Niño typically raises the mean temperatures in Arizona, which can prevent snowfall from turning to snowpack at lower elevations. Melted snowpack from Arizona’s mountains is crucial to the Valley’s water supply.

“We want that snowpack. We want that water supply. But it’s kind of a double-edged sword here when it comes to El Niño. Yes, we’ll have more storm opportunities, but when you look at a more mild air mass, it does affect the snow levels,” Malloy said.

What is the status of the 2026 monsoon season?

The 2026 monsoon season, which ends Sept. 30, has been drier than normal in Phoenix, even after last week’s storms.

Daily chances for isolated to scattered showers and storms return to the high terrain in eastern Arizona beginning this afternoon and evening. Slight chances spread into the lower deserts of south-central AZ on Wednesday and Thursday. #azwx pic.twitter.com/4hvX7xLG0Z

— NWS Phoenix (@NWSPhoenix) September 22, 2026

Phoenix Sky Harbor International Airport, which the National Weather Service uses for the city’s official readings, has received only 1.41 inches since the monsoon season started June 15. The normal season total is 2.43 inches.

There is still time to bolster the total before the season ends. The latest forecast shows a 30% chance for rain Wednesday night.

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