Monsoon Season

Rain shafts from a monsoon storm | source

I live in Arizona and we have a yearly monsoon season. It's a pretty interesting kind of weather event and can produce some scarily impressive duststorms so I thought I'd talk a little about it and share some pictures.

During monsoon season, moist winds from the south push up into the area, triggering thunderstorms. Arizona has historically received up to 50% of its annual rainfall during this time. The start of monsoon season used to be variable - there had to be 3 consecutive days of dew points (temperatures when condensation will occur) of 55°F or higher. That was changed 18 years ago to simply be from June 15 to September 30.

Overhead view of a large residential area with a rain shaft on the left and an incoming haboob on the right.

Dust storm moving in, July 13, 2026 Photo: Patrick Breen/The Republic | source

Except for a 5 year break, I have lived in Arizona since 1981. Monsoon thunderstorms used to be more predictable. Once the season got started, thunderstorms would roll in many afternoons. Now the thunderstorms are more sporadic, an effect I think of both climate change and also our urban heat island. But, in addition to being fewer in number, when they do come it's with more intense rain and wind as well as just more rain at once. Often the dry desert is unable to handle the sudden deluge of intense water. There have always been floods and property damage associated with the monsoon season but it feels like the changing quality of the monsoon is making it worse.

photo of city scene with a freeway in the foreground and buildings in the background. A large haboob is coming in from the left.

The dust storm that hit Phoenix on July 5, 2011, popularized the term "haboob." Photo: Mike Olbinski | source

Sometimes the thunderstorms are preceded by a haboob, a massive windstorm pushing a wall of dust. The term comes from an Arabic word, habūb, which means blowing furiously. It was only after a particularly massive dust storm in 2011 that they started being referred to as haboobs in Arizona.

Photo of an airport with a large haboob coming in the background.

Haboob at Phoenix Sky Harbor International Airport Photo: City of Phoenix via Associated Press | source

Are there any interesting seasonal weather events that happen in your area?

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