El Niño strengthened again over the past fortnight, with the Bureau of Meteorology's climate driver update on Tuesday putting the key Pacific index at 1.47 degrees above average, nearly double the threshold that defines the event.
"The majority of models indicate this event could peak at levels among the highest observed since 1950," the Bureau said in the update. "It is likely this El Niño will persist until at least summer." That is firmer language than mid-June, when the Bureau declared the event and around half of surveyed models pointed to a peak of that scale.
A second climate driver may be forming beside it. The Indian Ocean Dipole is neutral for now, with the weekly index at minus 0.06 degrees, but the Bureau's update says models suggest a positive IOD event is likely to develop over winter and persist into spring. When a positive IOD sets in alongside El Niño, the two tilt southern and eastern Australia toward less rain and higher temperatures through spring.
The Bureau's ocean data shows the warmth is not confined to the tropics. Sea surface temperatures for the week ending July 12 were two to three degrees above average along the New South Wales and eastern Tasmanian coasts.
Scientists put ranges around what that means on the ground when the event was declared last month. "Australians should be vigilant about the summer that lies ahead, as the scales are now tipped towards drought conditions, longer and more severe heatwaves," the Australian National University's Sarah Perkins-Kirkpatrick said. The University of NSW's Andrea Taschetto offered the counterweight: "Not necessarily a strong El Niño event means severe impacts on the ground. Past strong El Niño events such as 1997-98, 2015-16, 2024-25 had only weak or moderate impacts."
None of it has arrived yet. On Wednesday morning the Bureau had a frost warning current for Victoria's North East district, issued on Tuesday evening, with minimums near zero, and Canberra woke to frost and fog patches ahead of a sunny afternoon. The Pacific is warming while the paddocks are still white.
The Bureau's next climate driver update is due in a fortnight, with the winter-spring rainfall outlooks that follow it the numbers for farmers and fire agencies to watch.
