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.

This chapter begins with an account of the roles of Charlemagne and Alcuin in supporting the study of computus and astronomy in the Carolingian Empire. It then offers an outline of the expanded astronomical and meteorological information found in Carolingian ‘encyclopedias’ of computus. A key problem for users of these collections was the lack of accurate astronomical observations and calculations, which enforced continuing dependence on lists of short-term ‘signs’ of coming weather, mostly derived from Pliny. One attempt to improve the range of knowledge available took the form of beautifully illuminated versions of Aratus’ long poem, in volumes known as Aratea. The dissemination of this body of information is traced through analyses of surviving manuscripts, which demonstrate the resources being devoted to the subject across mainland Europe. Separate consideration is given to Anglo-Saxon England, where Viking conquests and wars had caused serious disruption, and where the teaching of Abbo of Fleury, and his pupil Byrhtferth, was crucial. The chapter argues that possession of superior astronomical and meteorological knowledge was highly vaued by rulers in both secular and spiritual spheres.

The Conclusion traces the importance of astrometeorological forecasts from the seventeenth century onwards. It finds surprising evidence that they finally disappeared only in the nineteenth century, despite increasing criticism. In fact, one of the attackers mourned the continuing high sales of Moore’s almanac in the 1830s. A central finding is that the increasing rejection of astrology in the eighteenth century, and the attacks on astrometeorology, led to the absence of any accepted basis for making weather forecasts. This problem, together with ongoing demand for knowledge of coming weather, led to the revival of old-fashioned weather-signs. The support given by Tycho Brahe and Johannes Kepler to both astrometeorology and the keeping of waether records is considered, as are early modern treatises on weather prediction. A detailed study of English 18th-century almanacs shows use of weather journals and instruments such as barometers, alongside traditional astrometeorological methods. The final conclusion is that it was only the production of FitzRoy’s new, ‘practical’ system of forecasting the weather that finally ended the age of medieval meteorology.