The tropical climate is found around the two Tropics that is, the Tropic of Cancer and the Tropic of Capricorn. The tropical climate has two main varieties i.e., the Tropical Dry Climate and the Tropical wet Climate.
The tropical Dry Climate
This type of climate is found in almost all of the hot deserts of the world that include the Sahara Desert, the Arabian Desert, the Australian desert and the Indian desert; to name a few. The characteristic feature of this type of Climate is the extreme heat and cold of the summer and winter seasons respectively and a very scanty rainfall. To take a typical example we consider the world famous city of Cairo.
At Cairo, the total annual rainfall is only one inch and the temperatures vary greatly in summer and winter. On one hand, at the height of summer, the mid-day thermometer can easily exceed 110 F while on the other hand during a severe cold spell in winter, the air temperature can dip below 40 F.
The air is exceptionally dry and the relative humidity very low, especially in the afternoons.
The tropical Wet Climate
This climate is found in India, Thailand, Myanmar, Bangladesh, Latin America and the Savanah of Africa. The characteristic feature of this type of climate is a definite wet season preceded by a hot dry season. Rainfall can be exceptionally heavy during the wet season. Sometimes as much as 10 inches can fall within 24 hours.
Mumbai, India, is a typical station of this type of Climate. Here rain exceeds 15 inches for three months of the year and the total annual rainfall is around 75 inches. Compare this figure with that of Cairo of only on inch which lies in the tropical dry zone.
The temperatures do not go as high as in the tropical dry climate and normally do not exceed 100 F at mid-day in summers. Once the rainy season is well established then the midday thermometer rarely exceeds 85 F.
The relative humidity is very high during the rainy season and figures above 80 percent can be recorded for days or weeks together during a strong wet spell.
In short, Tropical dry climate and the Tropical wet climate are basically different from each other. The former shows extremes of temperature with little or no rainfall while the latter exhibits exceptionally heavy rainfall and a very high relative humidity.