Aristotle reasoned that the area north of the Arctic Circle (66.5° north) and south of the Antarctic Circle (66.5° south) was permanently frozen. He called this uninhabitable zone the "Frigid Zone." We know that areas north of the Arctic Circle are indeed habitable. For instance, the world's largest city north of the Arctic Circle, Murmansk, Russia, is home to almost half a million people. Due to months without sunlight, residents of the city live under artificial sunlight but yet the city still lies in the Frigid Zone.
The only area that Aristotle believed was habitable and capable of allowing human civilization to flourish was the "Temperate Zone." The two Temperate Zones were suggested to lie between the Tropics and the Arctic and Antarctic Circles. Aristotle's belief that the Temperate Zone was the most habitable likely came from the fact that he lived in that zone.
Since Aristotle's time, others have attempted to classify regions of the earth based on climate and probably the most successful classification was that of German climatologist Wladimir Koppen. Koppen's multiple-category classifcation system has been slightly modified since his final classifcation in 1936 but it is still the classification used most frequently and most widely accepted today.