Home > Encyclopedia of Science > Monsoon

• General monsoon circulation
• Words to Know
• The monsoon of India
• When the monsoon fails

A monsoon is a seasonal change in the direction of the prevailing wind. This wind shift typically brings about a marked change in local weather. Monsoons are often associated with rainy seasons in the tropics (the areas of Earth within 23.5 degrees latitude of the equator) and the subtropics (areas between 23.5 and about 35 degrees latitude, both north and south). In these areas, life is critically dependent on the monsoon rains. A weak monsoon rainy season may cause drought, crop failures, and hardship for people and wildlife. However, heavy monsoon rains have caused massive floods that have killed thousands of people.

Many parts of the world experience monsoons to some...