El Niño has arrived and it could be the most volatile yet

El Niño events have driven droughts and led to dust storms in the past. (Supplied: Shae Ferguson)

An El Niño is underway in the Pacific, which could mean hotter, drier conditions in Australia, but scientists say climate change is making its impacts harder to predict.

This El Niño could be the strongest on record, but that does not necessarily mean Australia will experience record heat.

Experts are waiting to see how this El Niño affects rainfall and temperatures over the coming months.

As Australians brace for the second half of 2026 to be influenced by El Niño, scientists are warning that the impacts of the weather pattern are becoming harder to predict due to climate change.

The Bureau of Meteorology has officially declared an El Niño active in Australia, which refers to an extended period of warmer-than-usual water in the central and eastern Pacific.

It is the first time such a declaration has been made in almost three years and means much of the country is set to experience hotter and drier conditions over the coming months.

It was Peruvian fishermen, hundreds of years ago, who first noticed and named El Niño. Little did they realise they had named one of the most consequential climate drivers on Earth. This is how it works.

Modelling suggests this El Niño could become the strongest on record, but that does not necessarily mean Australia will experience record heat and drought.

Monash University adjunct professor and climate councillor Andrew Watkins said this event coincided with global temperatures increasing by about 1.5 degrees Celsius.

"With climate change, we've already boosted the risk of heat and fire weather and drought and even marine heat waves and coral bleaching," he said.

"El Niño adds to all of those, so increases the risk even further of having heat, drought, fire weather and coral bleaching as well.

Dr Watkins said scientists could still predict when El Niño and the cooler, wetter La Niña were likely to develop, but climate change was making their effects harder to forecast.

"We now have more moisture in the atmosphere for each degree of global warming," he said.

"With El Niño, long dry periods, cloudless skies, but when that weather does come that can bring a bit of rain, it could bring more rain than normal."

UNSW climate scientist Andrea Taschetto said research suggested El Niño and La Niña events could become more regular and intense, but the data record was short.

"The fact that we have a warmer atmosphere with more moisture in the atmosphere, that means that the impact of El Niño can be different than it has bee