 Additional highland areas in the subtropics also meet "Cs" requirements, though they, too, are not normally associated with Mediterranean climates, as do a number of oceanic islands such as Madeira, the Juan Fernández Islands, the western part of the Canary Islands, and the eastern part of the Azores.Under Trewartha's modified Köppen climate classification, the two major requirements for a "Cs" climate are revised.Under Trewartha's system, at least eight months must have average temperatures of or higher (subtropical), and the average annual precipitation must not exceed .