A monsoon is a seasonal shift in wind patterns that brings about alternating wet and dry periods. It is not just heavy rain but a large-scale seasonal change in the direction of prevailing winds, which causes changes in precipitation. Typically, during the summer, land heats up faster than water, creating low pressure that draws in moist air from the ocean, resulting in heavy rains. In contrast, in the winter, the cycle reverses with dry winds blowing from land to sea, leading to dry weather. Monsoons are crucial for providing water for agriculture but can also cause floods and droughts depending on the season and intensity.

Monsoons occur in many tropical and subtropical regions, including South Asia, West Africa, and parts of North and South America. The most famous example is the South Asian monsoon, which brings about 80% of the annual rainfall in India and significantly impacts agriculture and everyday life. The term "monsoon" comes from the Arabic word "mawsim," meaning "season," reflecting its seasonal nature.

In summary, a monsoon is a seasonal wind shift causing wet and dry cycles essential for ecosystems, agriculture, and human life, but also potentially hazardous due to flooding or drought.