The term ＇extreme＇ climates suggests that some climates have exaggerated characteristics in comparison with others that are more neutral and less extreme. By reducing the number of global climate zones to less than ten, a discipline of climatic description is forced that emphasizes their distinctive differences. Reviewed are the Arctic and Subarctic, and the maritime climatic zones. Simultaneously, indigenous architecture is examined as an indicator or telltale of climatic uniqueness, parallel to the use of vegetation types to define and distinguish biological climates. The snow igloo of the Inuit is examined in detail as both a constructive and operational environmental system. In comparison the Lapp winter hut or kata is also described. Although nominally examples of the temperate or maritime climate, the New England Cape Cod cottage is contrasted with the Hungarian village and house. A series of conclusions identify lessons from indigenous architecture appropriate to sustainability in industrial and post-industrial cultures.