Tropical rainforests grow in South America, the Congo, Indonesia and some nearby countries, Hawaii, and eastern Australia. Tropical rainforests are aptly named, as it rains here on about half the days. The only season in a tropical rain forest is summer, so plants grow for all 12 months of the year. Trees are tall and thick in the rain forest and they grow so close together that they seem to form a big umbrella of greenery called a canopy. This blocks out most of the sunlight. The air is muggy as it filters through the dense canopy cover of the trees. The light that filters through this tree cover is dim and green. Only along river banks and in places that have been cleared does enough sunlight allow plants to grow on the forest ground.