What is the monsoon?

We live in arguably the most beautiful desert in the world, the Sonoran Desert, which stretches from Central Arizona down into Mexico.

Under normal weather conditions, the Sonoran Desert experiences hot temperatures and very dry heat, but once the summer monsoon rolls around, temperatures drop and our humidity and dew point rise.

Annie Kwartler

A monsoon is defined as any wind that reverses its direction seasonally.

In late June and early July, the wind patterns to our south over Mexico begin to shift.  Winds flow out of the south and southeast, bringing in moisture from the Pacific Ocean, the Gulf of California and the Gulf of Mexico.

That moisture rises with our intense summer heat and produces thunderstorms across Arizona.

QUIZ: Understand the monsoon

These monsoon storms can produce heavy rain, dust storms, lightning, strong winds and flash floods.

In previous years, we tracked dew point temperatures to see when enough moisture had arrived to call it the monsoon.  The average start date was July 7th, usually lasting through mid-September.

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Now, the National Weather Service has set specific dates to our "monsoon season".  It begins each year on June 15th and lasts until September 30th.

While our summer monsoon can be exciting and even beautiful, storms can pop up in an instant and cause major damage.

Early notice is key to saving lives and property, so count on the ABC15 Forecasters to take action to keep you and your family safe this summer with the power of ABC15 Desert Doppler radar.

Take a look at the chart below to see highest Phoenix Rainfall Index (PRI) days since 1998.

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