Climate / Soil / Landforms

Tropical rainforests grow only in areas where rainfall, temperatures and humidity is high throughout the year. With the Equator running through the country, the Congo Basin climate is warm and humid; with two main seasons: one long rainy season and a dry season with slightly less rains. It rains about 117 days per year with a total of approximately 1,766mm of rainfall. Usually the rainy season begins in the first half of March and the dry season usually begins in November.

Rainforests are important regulators of the earth’s climate. They produce around 30% of the world’s oxygen.

Temperatures are fairly stable with little change between seasons, the greatest temperature between day and night usually averaging a change of 15° C. Temperatures range between 20° and 27° C, although near some river tributaries, the area cools to as low as 12° C. Humidity averages around 80 – 90 percent.

The Congo basin area encompasses the Congo River, which is the worlds’ second largest river based on water volume. The ranges also are separated by river gorges, which are tributaries of the Congo River. The largest, Mount Foungouti at the southern end of this Congo Basin region rises to 930 metres. In the north, these mountains are lower, only rising to around 650 metres.


The country’s drainage system is dominated by the Congo River. The area is heavily coarse grained soils, about 60% contains sand and gravel, with the lower lying areas having a high level of iron and aluminum oxides. The soils are rich and heavy, as organic matter decomposes rapidly because of the hot and humid climate, and also topsoil is washed away regularly by rains.