Australia experienced its second hottest September on record in 2026, with data pointing to a combination of ongoing climate change and an intensifying El Niño event as key contributing factors. The Bureau of Meteorology reported that average temperatures across the country were 2.71 degrees Celsius above the long-term average for the month, based on the 1961–1990 baseline. Minimum nighttime temperatures were also the highest ever recorded for any September, surpassing the previous record set in 2023 by a narrow margin.
Every state and territory registered September temperatures among their five warmest on record, with the Northern Territory marking its sixth warmest month of this type. The rise in temperatures was widespread, with elevated readings recorded in both urban and alpine regions. In New South Wales, 45 locations posted their warmest September on record. Meanwhile, alpine areas saw significant deviations from historical patterns, including Kosciuszko National Park, where snow depth dropped to zero in September for the first time since records began in 1954.
Dr. Linden Ashcroft, a climate scientist at the University of Melbourne, attributed the extreme warmth to climate change, emphasizing the phenomenon of seasonal creep, where winter is ending earlier and spring arriving sooner. “There’s only one clear driver of this and that’s climate change,” she said.
The impacts of El Niño, a climate system currently growing stronger in the tropical Pacific and predicted to be among the most intense on record, were also evident. Dr. Simon Grainger, senior climatologist at the Bureau of Meteorology, noted that persistent high-pressure systems over southeastern Australia resulted in warm and dry conditions. New South Wales registered its fourth driest September, and Victoria its sixth driest, contributing to an unusual deficit of cold days.
Rainfall was generally below average across the country in September, with the notable exception of Western Australia, which experienced its second wettest September on record and the wettest since 1904. In the Alps, temperature records were broken at several stations, with Mount Buller, Falls Creek, and Mount Hotham all recording their highest maximum temperatures for September.
At Thredbo, where temperature records span nearly six decades, the average nighttime temperature for September hit 0.1 degrees Celsius, marking the first time monthly minimums averaged above freezing for that month. The location also recorded its hottest September day at 16 degrees Celsius, exceeding the previous record from 2001 by approximately one degree.
The unprecedented warmth and dry conditions during September underline the significant and continuing impacts of global warming on Australia’s weather patterns, compounded by natural climate variability factors like El Niño. Since national temperature records began in 1910, the continent has warmed by more than 1.5 degrees Celsius on average, a trend that experts say is shaping Australia’s climate well into the future.