Changuu is a tropical island enjoying warm weather at most times, with a mean high temperature of 36 degrees Celsius from December to March, and a mean low temperature of 21 degrees Celsius July and August.
It is a coral islet lying approximately 6 meters above the high tide mark, consisting of coral rag and lying on a coral reef, much of which is exposed at low tide. In the healthy corals, excellent varieties of coral fish are found.
All over the island, there are a number of coral pits, which are disused quarries from digging coral for building on Zanzibar Stone Town along the centuries. One large quarry site at the back side of the island is used as a natural swimming pool at which it is not unusual to swim with Green and Hawksbill sea turtles.
There are extensive areas of coral rag bush and indigenous tropical forest, which is interspersed with large variety of exotic trees. In the central part of the island, the thick covering of indigenous forest is host of introduced species of flora such as Indian Almond, Papaya, Citrus and Frangipani, scattered among the numerous indigenous trees. Some of salt marsh species such as mangrove forest are found at the southern part of the island.
The existence of coral rag bush has got a very significant importance to bare a wide variety of birds, colourful peacocks, bats, butterfly and a good variety of insects, with some duikers.
Separate mention, given its importance, deserves the community of Aldabra Giant Tortoises, a species endemic to the Aldabra archipelago in Seychelles, that inhabit Changuu Island since the 1920s. Initially, 4 tortoises came as a gift of the Seychelles Government to the Government of Zanzibar, and the community has grown until become made of over 100 individuals. Today, the Save the Tortoises foundation secures their welfare at the Tortoise Sanctuary.