It's the later half of July and soon to be early August and that means it's time once again to talk about the North American Monsoon. 

The word “monsoon” comes from the Arabic word mausim, meaning season. Basically, it describes a seasonal wind shift over a region that is usually accompanied by a dramatic increase in precipitation. Many of us are familiar with the Indian-Asian monsoon that brings heavy rains during the summer months over widespread areas of India and SE Asia. Although these rains often produce major flooding, they are vital to agriculture and the economy. Because so much of the world's population live in this region, a delayed or reduced rainfall season can have a devastating effect on the livelihood of a significant fraction of the world's population.

Many other parts of the world experience monsoons, including North America. Our North American monsoon (also known as the Mexican monsoon) typically occurs between July-September and is relatively small compared to the Asian monsoon. However, in parts of NW Mexico, over 50% of the annual rainfall comes in this 3-month period. The rains provide a critical source of replenishment for water resources of Mexico and the SW United States.

CoCoRaHS volunteers can play an important role and possibly save lives by sending in a real-time "Significant Weather Report" when heavy precipitation falls during flooding monsoonal rains. Check out our “How to Measure Heavy Rainfall” animation.

To learn more about the North American monsoon, please take a look at this very informative page put together by the National Weather Service Office: “Monsoon” Also you can watch Chris Castro’s WxTalk Webinar on the “North American Monsoon” which presents us with a lot of great information.