This chapter looks at Greek and Roman approaches to climate and weather, showing how geographers, astronomers, and physicians organised and understood geographical differences, and the consequences of those differences for agriculture, navigation, and even human physiology and disease. In some sources, very broad generalisations were made based on latitude alone, and in others variation was handled on a much more local basis. Long-term prediction of local weather was seen as an important task and utilised methods from astronomy, astrology, and folklore alike.