This chapter provides definitions of contrasting classical and medieval approaches to meteorology. It outlines the relevant works of Aristotle, as well as the means by which selections from these were transferred to Roman writers. The roles of Pliny and Virgil are considered, together with their own reception by early medieval writers. A key point is that patristic writers, especially Augustine, integrated this knowledge of the natural world into Christian teachings on cosmology. However, Aristotle’s arguments on meteorology were primarily transmitted to Latin Europe in Islamicate versions, and came accompanied by new information on astronomy. The chapter then offers an account of the transition from classical, theoretical models of climate to more detailed calculation of planetary movements and their alleged meteorological effects. An important argument is that early medieval scientific work is often presented in diagrams and tables, themselves found in monastic works on the ecclesiastical year, and are easy to miss or underestimate.