In the 1820s and 1830s, British settlers in Australia relied on folk theories, memories and patchy weather data to understand the past and future climate of their new settlements. A lengthy drought in New South Wales from 1826–1829 buoyed belief in a folk climate theory called ‘the septennial theory’ – the idea that south-eastern Australian climate was dominated by drought periods of seven years in length, followed by a seven-year period of good rainfall – and challenged the way British settlers had understood Australian weather and climate during the preceding 40 years of colonization. In the late 1700s, while Australia’s suitability as a penal colony was assessed, it was presumed that the temperate climate could support the ample production of both traditional English goods and produce, as well as exotic tropical crops in only a few short decades. South-eastern Australia’s expansive, temperate regions, lacking Britain’s wintery extremes, were brimming with agricultural and pastoral possibility. However, 30 years later, British settlers had faced lengthy, desiccating droughts interspersed with periods of high rainfall. In those few short decades, a wider understanding of Australia’s highly variable climate had started to emerge. The ‘septennial theory’ pre-dated the widespread establishment of meteorological weather stations that occurred in later decades. In the absence of long-term meteorological observations, it was preconceptions and theories that coloured the way colonisers viewed weather and climate in Australia and the way settlers reacted to its extremes. With a focus on the 1820s and early 1830s, this paper shows the way weather and climate was conceptualised in Australia in the absence of a strong meteorological tradition
