Tropical Moist Climate Tropical Moist Climates (Af)

In an average year in a tropical rain forest, the climate is very humid because of all the rainfall, which amounts to about 250 cm per year. The rain forest has lots of rain because it is very hot and wet. This climate is found near the equator. That means that there is more direct sunlight hitting the land and sea there than anywhere else. The sun warms the land and sea and the water evaporates into the air. The warm air can hold a lot of water vapor. As the air rises, it cools. That means it can hold less water vapor. Then as warm meets cold, condensation takes place and the vapor forms droplets, and clouds form. The clouds then produce rain. It rains more than ninety days a year and the strong sun usually shines between the storms. The water cycle repeats often along the equator. The main plants in this biome are trees. A lot of the rain that falls on the rain forest never reaches the ground. It stays on the trees because the leaves act as a shield, and some rain never gets past the trees to the smaller plants and grounds below. Trees in this climate reach a height of more than 164 feet. They form a canopy. The forest floor is called understory. The canopy also keeps sunlight from reaching the plants in the understory. Between the canopy and understory is a lower canopy made up of smaller trees. These plants do receive some filtered sunlight.

The tropical rain forest is classified as Af meaning tropical forest The A is given to tropical climates that are moist for all months which have average temperatures above 18 degrees Celsius. The f stands for sufficient precipitation for all months. The latitude range for rainforest climate is 15° to 25° North and South of the equator

The annual precipitation of a rain forest is greater than 150 cm. In only a month the rain forest receives 4 inches of rain. The rain forest is different from a lot of other climates. In other climates, the evaporation is carried away to fall as rain in far off areas, but in the rain forests, 50 % of the precipitation comes from its own evaporation.


The plants that make up the understory of a rainforest have adapted to the small amount of sunlight that they receive. Ferns and mosses do well, along with epiphytes. These are plants that grow on other plants. They can be found growing on branches of tall trees where they can get sunlight. There are many different plant species found in the rain forest.

by Michael G.  2001



"Köppen's Climate Classification - a summary", (Nov 2000)

"Biomes and Soils", (Dec 2000)

"rainfall", (Dec. 2000)

"temperature", (Dec. 2000)

Allaby, Michael. Biomes of the World Volume 7. Oxford: Andromeda Limited 1999

Kellert ,Stephen R. Macmillan Encyclopedia of the Environment. Simon and Schuster, Prentice Hall International. 1997

"Passport to the Rainforest", (March 2001)

World Biomes