Understanding of the importance of medieval astronomy and astrology is often undermined by the assumption that these fields of study were defined in the same way in the medieval period as they are now. It is also often claimed that medieval, Christian theologians were deeply hostile to all forms of astrology. The first part of this paper will show that both these ideas are mistaken, before moving on to outline the rise of weather forecasting by astronomical/astrological methods.
The main part of the lecture will demonstrate the techniques involved in making these predictions and then examine the practice of meteorological record-keeping which was associated with this science. Starting in thirteenth-century Oxford, and continuing through the Astro-meteorological work of Brahe and Kepler, proponents of the science recorded assessments or actual measurements of wind, precipitation, sunshine and temperature, and correlated these against planetary configurations as viewed from their locality. Their aim was to refine their weather predictions by linking them to local climatic conditions. Of course, this proved unsuccessful; but it was nevertheless an important part of the formation of empirically-based weather science.