Many Arabic geographical texts from the medieval period portray the oecumene as comprising seven latitudinal climes. In general the middle clime, in which the majority of Muslim territories were located, was viewed as possessing the best environmental conditions, which progressively deteriorated the further one travelled north or south of this central territory. This theory of the climes was combined with ideas of humoral pathology in order to argue that those living in the central zones of the oecumene received numerous physiological and psychological benefits. Conversely, those like the Africans and the Turks, living at the peripheries of the oecumene, had neither rationality nor proportionate physiognomies because their humours were distorted by the harsh environmental conditions of these regions. This article, however, seeks to nuance the outline given above. While secondary studies have generally been happy to adopt uncritically this superficial understanding of the medieval Islamic worldview, which is gained from skimming the introductions to a few geographical works, few have questioned what (and where) is meant by the centre of the world, where did human habitation supposedly end, and was the medieval understanding of the seven climes uniform. These are some of the questions posed by the present investigation. I then go on to assess how far the notions derived from the theory of the climes were implemented in ethnological accounts of the inhabitants of the far north and south. In doing so I shall conclude that the standard conception of the medieval Islamic worldview masks numerous disagreements and debates in the writings of medieval scholars.