This essay introduces a new technique to improve the reliability of the interpretation of how weather and climatic factors have influenced past societies. Using the case of first European settlement in Australia, we argue that historians have largely ignored or misconstrued the influence of climate on past societies. We discuss how cool, wet weather during 1788–1790 (a La Niña) and the drought conditions of 1791–1793 (an El Niño) compromised initial settlement and agricultural development in the colony. We compare meteorological and palaeoclimatic data with historical sources to investigate how water scarcity has profoundly shaped Australian society since 1788.