An area of tropical monsoon climate (occasionally known as a sub-equatorial, tropical wet climate or a tropical monsoon and trade-wind littoral climate) is a tropical climate subtype that corresponds to the Köppen climate classification category Am. Tropical monsoon climates have monthly mean temperatures above 18°C in every month of the year and a dry season.[1] The tropical monsoon climate is the intermediate climate between the wet Af (or tropical rainforest climate) and the drier Aw (or tropical savanna climate).
A tropical monsoon climate's driest month has on average less than 60 mm, but more than . This is in direct contrast to a tropical savanna climate, whose driest month has less than 60 mm of precipitation and also less than of average monthly precipitation. In essence, a tropical monsoon climate tends to either have more rainfall than a tropical savanna climate or have less pronounced dry seasons. A tropical monsoon climate tends to vary less in temperature during a year than does a tropical savanna climate. This climate has the driest month, which nearly always occurs at or soon after the winter solstice.[1]
There are generally two versions of a tropical monsoon climate:
Tropical monsoon are most commonly found in Africa (West and Central Africa), Asia (South and Southeast Asia), South America and Central America. This climate also occurs in sections of the Caribbean, North America, and northern Australia.
The major controlling factor over a tropical monsoon climate is its relationship to the monsoon circulation. The monsoon is a seasonal change in wind direction. In Asia, during the summer (or high-sun season) there is an onshore flow of air (air moving from ocean toward land). In the “winter” (or low-sun season) an offshore air flow (air moving from land toward water) is prevalent. The change in direction is due to the difference in the way water and land heat.
Changing pressure patterns that affect the seasonality of precipitation also occur in Africa, though it generally differs from the way it operates in Asia. During the high-sun season, the Intertropical convergence zone (ITCZ) induces rain. During the low-sun season, the subtropical high creates dry conditions. The monsoon climates of Africa, and the Americas for that matter, are typically located along trade wind coasts.
Asia
Oceania
Africa
The Americas