This article uses a modified version of a classification system introduced in 1918 by Wladimir Koppen, a German climatologist. Koppen based his system on a region's vegetation, average monthly and annual temperature, and average monthly and annual precipitation. Tropical wet climates are hot and muggy the year around. They support dense tropical rain forests. Rainfall is heavy and occurs in frequent showers and thunderstorms throughout the year.
Temperatures are high, and they change little during the year.
The temperature difference between day and night is greater than the temperature difference between summer and winter. Frost and freezing temperatures do not occur. Plants grow all year. Tropical wet and dry climates occur in areas next to regions that have tropical wet climates. Temperatures in tropical wet and dry climates are similar to those in tropical wet climates, where they remain high throughout the year.