Australia has just experienced its hottest summer in a decade, with the season ranking as the eighth warmest on record. Data from the Bureau of Meteorology reveals that over 60 weather stations recorded their highest ever daily maximum temperatures during a heatwave in late January.
The summer was notable not only for scorching days but also for exceptionally warm nights. Australia recorded its fifth-warmest summertime night temperatures on record. At least nine weather stations saw minimum temperatures remain in the 30s or high 20s Celsius through the night on consecutive days, particularly on 28, 29, and 30 January.
High night-time temperatures pose significant health risks, including strain on the cardiovascular system, kidneys, and mental health. Disturbed sleep hampers recovery from hot days, increasing vulnerability for older Australians and those with comorbidities. Dr Aaron Bach from Griffith University notes that heat exacerbates chronic conditions such as cardiovascular disease, renal conditions, and mental health illnesses.
Heatwaves are the deadliest climate hazard in Australia, with more than half of heat-related deaths occurring in the most disadvantaged areas. Climate change is driving an increase in the frequency and intensity of extreme temperatures. A recent CSIRO report found that very high night-time temperatures now occur five times more often than between 1960 and 1988.
Experts emphasise that both the intensity and duration of heatwaves are critical. Professor Ollie Jay from the University of Sydney explains that factors like activity, clothing, and environment compound temperature risks. His HeatWatch app models risk scores, showing that an 82-year-old with cardiovascular disease faced 'severe' or 'extreme' heat risk during the heatwave, with 'high' risk persisting overnight.
