Saint Vincent and the Grenadines is comprised of thirty four islands. Saint Vincent is the largest island located at 13°15’ N latitude, and 61°1’ W longitude. It has the most rugged terrain of the island grouping with the highest point at 1234m at the top of the La Soufriere Mountain found within the central range. La Soufriere is also an active volcano which last erupted in 1979. South of Saint Vincent is Bequia and further south are the islands of Mustique, Union Island, Canouan, Palm Island and Mayreau. These are all inhabited, unlike the Tobago Cays which is a grouping of 5 uninhabited islands. Unlike St. Vincent, the other islands have a more gentle topography and limited surface water. The University of the West Indies Seismic Centre notes that the islands rocks are volcanic in origin, namely andesites, basaltic-andesites and xenoliths. Saint Vincent has an average annual rainfall of 3800mm in the central mountain area and around 2000mm on the coast. The average yearly temperature is 27°C. The rainy season is from May to October.