Climate is classified into smaller units called climatic regions for easy understanding. V Köppen classified the most commonly used climatic regions. The classification is based on the distribution of vegetation and climate. Rudolf Geiger later added changes to the classification, leading to the system often being called Köppen-Geiger classification. In this classification system, the world’s climate is divided into five major climatic regions. This article will focus on two climatic regions: Equatorial Climatic Region and Tropical Monsoon Climate.

Koppen Climate Classification

Koppen classified climate into five major regions, they are:

• Tropical Climate (A) – Does not go below 18 °C, relatively hot climate. Usually humid
• Dry Climate (B) – Dry because the evaporation rate is higher than precipitation
• Warm Temperate (C) – In the coldest month, the climate is between 3 and 18 °C.
• Cold Snow Forest Climates (D) – The coldest month goes below 3 °C
• Cold Climate (E) – In these regions, never over 10 °C, relatively cold climate

As seen in the table, the capital letter next to the climate type denotes the symbol associated with that climate group. Each of these climatic regions is further subdivided into types denoted by small letters. The capital and small letter combination denote the subtype of climate under Köppen’s classification. Subdivision of regions is based on temperature and seasonality of precipitation. The following table lists subdivisions of the climatic regions listed above.

Tropical Regions

The Tropical Region falls between the Tropic of Cancer and the Tropic of Capricorn. The Tropic of Cancer situated at the 23.5°N latitude forms the northern limit of the region, and the southern limit falls on the Tropic of Capricorn situated at 23.5°S latitude.  

The Equatorial Region often falls under the Tropical Region. The Equatorial Region extends from 3°N to 3°S latitudes. On the other hand, Equatorial Climate is stated to be the climatic type extending from 10–12°N and 10–12°S of the equator. So Equatorial Climate is a subtype of Tropical Climate. We will discuss Equatorial Climate in detail in the next section.

General characteristics of tropical regions

• Temperature: Tropical climates have temperatures around 18 °C throughout the year. There is not much temperature difference between the seasons. Ancient Greeks referred to this region as the Torrid Zone, which perfectly describes the hot, dry weather in this region experiences
• Pressure and wind: The equator falls into the Intertropical Convergence zone while the Subtropical Regions experience the Subtropical anticyclones. This is the convergence of the Northeast trade winds and the Southeast trades
• Monsoons: Monsoon is a seasonal wind reversal experienced in many locations on Earth. Monsoons are best developed in southern and eastern Asia, especially over the Indian Ocean and the westernmost Pacific. Monsoons are directed from ocean to land. Winters are usually much drier
• Trade wind inversion: Inversion of trade winds is the most crucial factor influencing the thermal structure of the Tropical oceanic atmosphere

Equatorial Climatic Region

Equatorial climates are usually hot and wet throughout the year. It is ideal weather for rainforests, and so most of the world’s rainforests are located in this region. The rains, along with the hot weather, lead to the Equatorial climate being extremely humid. Equatorial Regions experience high rainfall and constant temperatures. 

Equatorial climate has the same characteristics as Tropical Climates because Equatorial Regions are subtypes of Tropical Climatic Regions.

Equatorial climate regions: South America, Central America, Central Africa, South East Asia, Indonesia, Malaysia, and Sri Lanka,  and other places near the equator like Costa Rica, Kenya, and Borneo and parts of South America including Venezuela, Columbia, Brazil, and Asian countries like Vietnam.

Tropical Monsoon Climate

Tropical Monsoon Climates are one of the rarest Climatic Regions in the world. This region experiences rainfall of 1000 mm. Like other Tropical Climates, the Tropical Monsoon Climate also has consistent temperatures throughout the year. It shows minimal variance in temperature through the various seasons in the year. The days after the winter solstice are usually the driest in the year.

Regions with Tropical Monsoon Climate receive rain through monsoon winds blowing from the sea in summer. These monsoon winds determine the precipitation in parts of Asia, the Pacific Ocean, and the Indian Subcontinent’s monsoon. Tropical Monsoon Climate can further be divided into less pronounced dry seasons and rainy wet seasons with pronounced dry seasons. We will take a look at the two versions in the next section.

Tropical monsoon climate regions: Most commonly found in West and Central Africa, South and Southeast Asia and, South and Central America; the Caribbean, Northern Australia, and select regions of North America. Parts of Sri Lanka, Indonesia, Philippines, Cambodia, the southern tip of India, Taiwan, Myanmar, Australia, New Guinea, Sierra Leone, Liberia and Nigeria, among many other isolated pockets in countries within the Tropical Region. 

Variations of Tropical Monsoon Climate:

Less Pronounced Dry Seasons: Regions that enjoy this version of Tropical Monsoon Climate experience heavy rainfall and frequent thunderstorms in the wet season. The dry season also experiences rainfall above the average rainfall in Tropical Climates during the dry seasons. The difference between wet and dry seasons is less pronounced.

Pronounced Dry Seasons: In this variation of the Tropical Monsoon Climate, the dry season, although similar in length, has significantly less rainfall. The dry season is similar to the Tropical Savanna Climate in terms of duration and character. The dry season is followed by a period of pronounced precipitation over 1000 mm. 

Conclusion

Both Equatorial and Tropical Monsoon Climatic Regions are subtypes of Tropical Climatic Regions. The Köppen-Geiger system forms the basis of the classification of world climate into Climatic Regions. Characteristic features of these regions are consistent temperatures, no temperature difference between seasons, and persistent high rainfall. Tropical Monsoon Regions are found among Tropical Climatic Regions.