It’s the height of summer and many Australians have already experienced heatwaves, heavy rains and even significant bushfires over the Christmas and New Year period. But could we be in for something different as summer draws to a close?

Lower sea surface water temperatures in the central Pacific Ocean are leading to speculation about a La Niña event starting to form, raising the risk of wet weather. That would be unusual because La Niña events typically start in winter and get going properly in spring, before “decaying” in late summer and autumn.

Given the time of year, it would be hard for a proper La Niña event to get going now. But the Bureau of Meteorology’s outlook does point to a probable wet end to summer over most areas of Australia.

La Niña events are characterised by below-average temperatures in the central and eastern tropical Pacific Ocean and warmer waters in the west nearer to Australia. They often, but not always, bring wetter conditions for eastern and northern Australia.

In autumn, the variability in tropical Pacific Ocean temperatures starts to settle down, so it would be very hard for a La Niña to start in January and be maintained through to April. Indeed, we often see blips of warmer or cooler conditions at this time of year.

The Bureau of Meteorology has not declared a La Niña and instead notes that the El Niño-Southern Oscillation (ENSO) is currently “neutral”“ (neither El Niño nor La Niña), albeit with some indices drifting close to La Niña thresholds. Any unofficial declaration of a La Niña is jumping the gun.

La Niña is just one of many factors that can affect Australia’s weather.

Ocean temperature and wind patterns in the Indian Ocean, Southern Ocean and tropics all combine to influence our day-to-day weather. While La Niña events are often wetter on average, cooler waters in the Eastern Pacific do not guarantee rainfall and floods.

Our recent study of the unusually wet 2022 in Eastern Australia (the most recent La Niña period), found La Niña can help promote the background conditions needed for heavy rainfall, such as more onshore winds over Eastern Australia.

But it is the chaotic, and sometimes unlucky, behaviour of the day-to-day weather systems such as tropical cyclones, highs, lows and cold fronts that ultimately bring the extreme weather. Therefore, it is foolish to look at climate drivers such as La Niña in isolation to forecast the weather and climate.

This is why the Bureau is moving away from forecasts that focus on individual climate drivers like La Niña and are instead emphasising their long-range forecast, which takes into account all the drivers of Australia’s weather.

This shift in communication of climate information is partly due to an effort to end sensationalist reporting on El Niño and La Niña that can lead to public misunderstanding.