A monsoon (from the Arabic mawsim , which means “season”) arises due to a difference in temperatures between a land mass and the adjacent ocean. is a seasonal wind shift over a region. The wet monsoon begins when winds bringing cooler, more humid air from above the oceans to the land. A dry monsoon typically occurs between October and April. Instead of coming from the oceans, the winds tend to come from drier, warmer climates such as from Mongolia and northwestern China down into India.