Wondering how our desert region in the Southwest gets most of its rain? The North American monsoon! But the season is officially wrapping up.

It's been some time since we have seen daily rain and thunderstorm activity across the Southwest, the Great Basin, and Four Corners. In fact, our WeatherRadar archive shows the last time being September 15 into the 16th! With the North American monsoon season lasting from June to September, things are right on schedule to start winding down.

The North American monsoon is driven by a moisture influx from the Gulf of Mexico and the Gulf of California into the Southwest. Read more about it here.

This time of year, the overall wind flow has begun to shift back to its "regularly scheduled programming," out of the west. This brings a much drier air mass and the Southwest goes back to being more desert-like.

Although much of the Southwest gets its yearly rainfall from the North American monsoon, seasonal storms, and even tropical weather, - remember Hilary? - bring more precipitation to the region, including mountain snow. As the season shifts, keep an eye out for these storms on the WeatherRadar.