Science & Hidden Forces Driving Arizona’s Fascinating Monsoons

We often joke that our weather is so similar from day to day that we can just copy and paste the weather report from one day to the next. Arizona experiences gradual, subtle changes throughout the seasons, where it's a little warmer or a little colder, but overall, there isn't a great variance.

The big, rain-laden monsoon clouds are a hallmark of the annual weather system. | Canva

Except during the monsoon season. Arizona's monsoon season is a fascinating meteorological phenomenon, and it really puts a new spin on our daily weather patterns.

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From big, heavy clouds that roll into our skies, building up over the course of the day, to dramatic lightning shows, to sudden cloudbursts that can last anywhere from minutes to hours, as they swirl around us.

The lightning storms are so intense that scientists study them in Arizona.| Canva

What Causes the Monsoon in Arizona?

According to the National Weather Service:

The monsoons are driven by large-scale wind shifts that transport moist tropical air into the typically dry desert landscape.

The seasonal monsoon pattern officially runs from June 15th to September 30th. During this time, the monsoons bring 40-50% of our state's annual precipitation to the thirsty landscape.

Old Farmer's Almanac: Official Prediction for Arizona's Monsoon Season

Flash flooding is a real concern in the monsoon season. | Canva

What Makes Monsoon Season in Arizona So Intense?

Sudden Thunderstorms: Moisture from the Gulf of California and eastern Pacific Ocean fuels powerful afternoon and evening thunderstorms.
Flash Flooding: The desert is usually so dry that as the rains pour down, the soil struggles to keep up with the sudden deluge. This can lead to rapid runoff and dangerous flash floods.
Lightning Activity: Arizona gets so much lightning that scientists study it here. Our state experiences a high number of lightning strikes during monsoon season, which makes it one of the most electrically active periods of the year.
Extreme Temperature Swings: It's a strange contrast: Arizona needs the heat to fuel the monsoonal rain, which can lead to scorching temperatures, and the rains bring relief from the intense heat.

Is This Climate Pattern Bad News for Arizona's Summer Monsoon?

The skies are beautiful during the rainy season in AZ.| Canva

What Makes Arizona's Monsoons So Interesting

Arizona is blown by dry westerly winds most of the year. As the summer heats up, the winds shift to the south, pulling moisture from the Gulf of California and the Pacific Ocean.

The influx of moisture fuels the monsoon's powerful thunderstorms, which is why we suddenly get downpours and strong winds

5 Ways to Prepare Your Arizona Home for Monsoon Season

Every monsoon season is a little different. Some years bring a bountiful, above-normal rainfall, and other years, not so much. Global El Niño and La Niña weather patterns influence the strength, length, and intensity of the annual monsoon.

Localized weather patterns are very pronounced in the monsoon season.| Canva

Despite the chaos, the monsoon season is essential for Arizona’s ecosystem. It helps refill our water table, lakes, and tributaries and cools down the scorching summer temperatures. It's intense, but it's one of the most amazing things about living in the desert.

Sources: ASU | Mesa Connection | ASU Climate Office | National Weather Service