What is the definition of monsoons

The word "monsoon" is derived from the Arabic word "mausim" which means season. Ancient traders sailing in the Indian Ocean and adjoining Arabian Sea used it to describe a system of alternating winds which blow persistently from the northeast during the northern winter and from the opposite direction, the southwest, during the northern summer. Thus, the term monsoon actually refers solely to a seasonal wind shift, and not to precipitation.

Even though the term monsoon was originally defined for the Indian subcontinent, monsoon circulations exist in other locations of the world as well, such as in Europe, Africa, and the west coasts of Chile and the United States. Arizona happens to be located in the area of the United States that experiences a monsoonal circulation. During the summer months, winds shift from a west or northwest direction to a south or southeasterly direction. This allows moisture from the Gulf of California and the Gulf of Mexico to stream into the state. This shift in the winds, or monsoonal circulation, produces a radical change in moisture conditions statewide.

This monsoonal circulation is typically referred to here in Arizona as the Arizona monsoon. What we experience during the summer months, however, is only a small part of a much larger circulation that encompasses not only Arizona, but much of the southwestern United States and northwestern Mexico. Thus, it sometimes is also known as the Mexican monsoon. Others call it the North American Monsoon.