IN BRIEF
- Australia's El Niño could see Pacific sea surface temperatures climb more than 3C above average.
- The BoM says rainfall will vary across Australia, with parts of the south-east facing a drier end to the year.
Australia's current El Niño could become the strongest on record, but the Bureau of Meteorology (BoM) has cautioned that doesn't necessarily mean the country is headed for an exceptionally hot and dry summer.
The BoM says models indicate the El Niño underway in the Pacific Ocean could produce the highest central tropical Pacific sea surface temperature anomaly since reliable records began in 1950.
But it has stressed the strength of an El Niño does not directly determine how severe its impacts will be in Australia, with several other climate drivers influencing rainfall and temperatures.
Could this be the strongest El Niño on record?
An El Niño occurs when sea surface temperatures in parts of the central and eastern tropical Pacific Ocean become unusually warm, triggering changes in atmospheric circulation and weather patterns.
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The BoM says the current event is likely to become the strongest recorded based on forecast sea surface temperatures in the central tropical Pacific.
During the 1982-83 El Niño, which currently holds the record, sea surface temperature anomalies peaked at around 2.6C above average in January 1983.
The current event is forecast to potentially exceed 3C above average.
However, the BoM has warned against assuming a stronger El Niño automatically means more extreme conditions for Australia.
"Every El Niño is different," it said in an advisory it released on Tuesday.
"A strong event can produce only modest effects in some regions, while a weaker event can have significant impacts."
Australia's weather is influenced by a combination of climate drivers, including El Niño, the Indian Ocean Dipole (IOD), surrounding sea surface temperatures and seasonal changes, as well as the longer-term effects of climate change.
The previous El Niño, which developed in spring 2023 and continued into early 2024, was considered a moderate-to-strong event.
What could El Niño mean for Australia's summer?
The current El Niño is likely to continue through spring and summer, although its influence on Australian rainfall typically diminishes around early summer.
The BoM's latest long-range forecast, issued on 10 September, shows most of Australia is likely to experience above-average temperatures over the coming months.
Rainfall, however, is expected to vary considerably across the country
Between October and December, below-average rainfall is likely across parts of south-eastern Australia, including southern NSW, Victoria and Tasmania.
Most of Western Australia, as well as some central and northern parts of the country, are instead forecast to receive above-average rainfall.
The IOD is currently neutral, but all climate models suggest a positive IOD could develop later in spring. A positive IOD can increase the likelihood of drier spring conditions, particularly across southern and eastern Australia.
Climate change is also increasing the likelihood of hotter summers and more frequent extreme heat events.
While El Niño can increase the chance of higher temperatures, the BoM says local conditions and short-term weather patterns will also be important in determining bushfire risk.
Why has it still been raining during El Niño?
Despite El Niño's association with dry conditions in Australia, 2026 has so far been wetter than usual across large parts of the country.
The year began with an active La Niña climate pattern and a very wet northern wet season before conditions rapidly transitioned towards El Niño during autumn. El Niño was underway by June.
Parts of Australia's interior also received unusually high winter rainfall, largely due to significant weather systems including two north-west cloudbands and strong cold fronts drawing tropical moisture from the north-west.
While winter rainfall was unusually high for an El Niño year, the BoM said it was not record-breaking overall. Large parts of eastern Australia and south-west Western Australia still experienced a dry winter.
The BoM also pointed to unusually warm oceans around Australia and globally, which can provide additional moisture and energy for rain-producing weather systems.
Australia's overall water storages were around 71 per cent full in early September. Capital city storages were above 80 per cent, with the exceptions of Melbourne at around 70 per cent and Perth at around 40 per cent.
Conditions have been drier than average this year in parts of north-eastern NSW and south-eastern Queensland, south-west Western Australia and Tasmania.
The BoM also cautioned against drawing direct comparisons between Australia's coming summer and the extreme heat experienced recently across Europe and North America.
There is no predictive link between a northern hemisphere summer and the Australian summer.
However, it said recent overseas conditions demonstrated how extreme heat could rapidly dry vegetation, increase fire intensity and cause fire conditions to escalate quickly.
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