The Bureau of Meteorology has declared that La Niña is officially over, with forecasts now pointing at a rapid transition to El Niño later this year.

The Bureau’s latest Southern Hemisphere Monitoring report, issued on March 31, declared that “the 2025-26 La Niña has ended.”

This declaration ends a La Niña episode that started in spring last year and contributed to above average rain over large areas of northern and central Australia.

The past six months had clear hallmarks of La Niña, with widespread above-average rain, flooding in multiple states and even drought relief in some parts of the country.

It was, however, a relatively weak La Niña and did not bring wetter-than-usual weather to some parts of Australia. This is a good reminder that no two La Niña events are the same and their impacts can vary considerably from one La Niña to the next.

What comes next for Australia?

The Pacific Ocean has now transitioned into a neutral state, meaning neither La Niña nor El Niño are in place. This neutral phase is likely to persist until at least late autumn, during which time the tropical Pacific Ocean will have little influence on Australia's weather.

Looking further ahead, there are strong signs that El Niño could emerge later this year.

While sea surface temperatures are currently near average at the surface of the tropical Pacific Ocean, there is a large pool of abnormally warm water building beneath the surface. This deep warm water is expected to emerge at the surface in the coming months, which increases the likelihood of El Niño.

Image: Forecast sea surface temperature anomalies in June 2026, showing a tongue of abnormally warm water in the central and eastern tropical Pacific Ocean, which is a clear sign of El Niño. Source: Bureau of Meteorology.

Most international forecast models, including the Bureau of Meteorology’s model, expect El Niño conditions to emerge sometime between late-autumn and late-winter and then persist into the second half of the year.

Some forecast models also suggest the possibility of a strong El Niño, or super El Niño, developing later this year. However, the strength of an El Niño does not always reflect the strength of its influence on Australian weather.

El Niño impacts on Australian weather

El Niño occurs when warmer than average water sits at the surface of the central and eastern tropical Pacific Ocean and cooler than average water lies at the surface of the western tropical Pacific. This sea surface pattern is associated with changes in wind and pressure in the overlying atmosphere, which act to reduce cloud and rainfall over parts of Australia.

Image: Typical impacts of El Niño in Australia. Source: Weatherzone.

El Niño typically contributes to below average rain and above average maximum temperatures over large parts of Australia. It can also enhance bushfire risk, increase the frequency and severity of frost and decrease the peak seasonal snow depth in the Australian alps.

Autumn predictability barrier

It is important to note that forecasting El Niño and La Niña is notoriously difficult at this time due to a phenomenon known as the ‘autumn predictability barrier’ (or ‘spring predictability barrier’ in the Northern Hemisphere).

This predictability barrier refers to forecast models having less reliability before and during autumn in the Southern Hemisphere, with model accuracy typically increasing during winter.

However, despite still needing to move past the autumn predictability barrier, there is strong consensus between forecast models that El Niño is on the way in 2026. So, while this outlook should still be treated with caution in the coming weeks, there are already clear signs that the transition to El Niño could be underway.