As in many areas of human knowledge, the notion of climate acquired a deeper historical content around the turn of the 19th century. Natural philosophers, geographers, and others became increasingly aware of climate's own history and its relation to human, plant and animal, and Earth history. This article examines several aspects of this “historicization” of climate.The lively 18th century discussion of the influence of climate on society is well known. Montesquieu is its most famous representative, but Voltaire, Hume, Kant, and others also participated. Their debate was literary more than scientific, their goal the understanding of man, not climate. Partly for this reason and partly because of the lack of good information on climates, they made no attempt to gather substantial climatic data. In fact, the importance of systematically collecting reliable data was scarcely understood in any area of natural philosophy before the last decades of the century [Cf.Frängsmyr et al.,1990;Feldman, 1990]. Instead, participants in the debate repeated commonplaces dating from Aristotle and Hippocrates and based their conclusions on unreliable reports from travelers. As Glacken wrote of Montesquieu, “his dishes are from old and well‐tested recipes” [Glacken, 1967, chapter 12]. This is not to say that the debate over climatic influence was not significant—only that its significance lay more in the history of man than in the atmosphe