Assessment of the Exposure of Australia to Tropical Cyclones Through a Climatological Model for Cyclone Weather Extent

Tropical cyclones (TCs) are among the most damaging natural hazards affecting Australia, and climate change may alter their frequency, tracks, intensity, and associated exposure. Historical records provide a baseline for assessing changes. Here, we develop a climatology‐based statistical model of TC weather extent using Australian Bureau of Meteorology estimates of the radius of the outermost closed isobar, wind radii, and positional uncertainty. Explicitly incorporating positional uncertainty allows long and heterogeneous historical records to be analysed while accounting for changes in record confidence. The model is applied to International Best Track Archive for Climate Stewardship records of 1960/61–2023/24 to examine: (1) the variability in TC formation across the Southeast Indian–South Pacific basin, (2) Australia's differential exposure to TCs from different formation areas, and (3) decadal variability in TC activity. Results show that 95% of TCs producing TC weather events in Australia had their early lifecycle between 107.5°E and 166°E. TC weather events occur annually along northern Western Australia and every 2 years along north‐east Queensland. Event likelihood depends strongly on formation longitude and early lifecycle direction, reaching ~95% for formation longitudes between 135°E and 143°E and decreasing eastward and westward. TC‐frequency trends are spatially heterogeneous, with no robust basin‐wide change since 1960. Periodic reassessment as historical records lengthen and improve may refine estimates of TC exposure, while formation longitude and early lifecycle direction provide climatological indicators of the potential for developing TCs to affect Australia. Overall, the findings provide a long‐term climatological basis for Australian TC exposure assessment and risk management.