Monday, June 29, 2009

When Is It Monsoon Season in Phoenix?

A former client’s question prompted this post, so thanks Jon!

According to Wikipedia:

The North American Monsoon (NAM) occurs from late June or early July into September, originating over Mexico and spreading into the southwest United States by mid-July. It affects Mexico along the Sierra Madre Occidental as well as Arizona, New Mexico, Nevada, Utah,Colorado, West Texas, and California.

When I was a kid and we moved here in the late 1970’s, the knee-jerk reaction answer to "When's the monsoon?" was “August”.

With the heat island effect, it seems like the monsoon arrives earlier and lasts longer each year. Last year, the National Weather Service announced they would date the monsoon season in Arizona from June 15 to September 30 each year. In prior years, the weather services had dated the beginning and ending of the monsoon season based on meteorological readings of the barometric pressure, temperature, humidity, etc.

Monsoon With a Dust Storm Chaser

Monsoon with a dust storm chaser originally posted on Kathy Anderson’s AZ Active Retirement Living blog

Monsoon Clouds Over Phoenix Skyline

monsoon over downtown Phx image courtesy of The Downtown Phoenix Journal

Monsoon near Quartzite Arizona, 1976

AZ monsoon near quartzite, AZ 1976 CDouglas Stockdale on DouglasStockdale DOT com photo courtesy of, and copyright by Douglas Stockdale

Video of Monsoon Storms

Here’s a really exciting video about Phoenix monsoons created by the local CBS news affiliate, channel 10 (hat tip to Kathy Anderson for linking me to it). The video clip is undated but it appears to be a retrospective of the 2008 monsoon season, which was one of the Valley’s 10 worst.

In the video, CBS reporters talk to a hi-rise condo owner in downtown Phoenix who shot video of the August 28 (2008?) storm as it swept across town, blew out the windows in his condo, and then proceeded to dump cherry-sized hailstones into his living room!

At about the 6:28 minute mark of the video, there’s a mind-boggling shot of a huge dust storm surging across the Valley. It reminded me instantly of the videos of the 2004 Indonesian tsunami.

Just the Facts, Ma’am

Are you the type who likes detailed statistical information instead of shocking videos? Here’s the National Weather Service explaining the meteorological in’s and out’s of monsoons. Local news AzFamily Channel 3 has some more great statistics on wind speeds and dollars’ worth of damages during monsoon season.

Related Posts and Information on Other Sites

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