Large parts of south-east Australia are expected to experience drier and hotter conditions over the next three months as a potential El Niño weather phenomenon develops in the Pacific Ocean. The Bureau of Meteorology has forecast lower than usual rainfall for much of Queensland and New South Wales in May, June and July, while almost the entire country is likely to see higher than average maximum temperatures.
El Niño's Impact on Australia
The World Meteorological Organization recently indicated an increasing chance of an El Niño developing in the Pacific, a phenomenon historically associated with hotter and drier conditions for Australia's east coast. El Niño events also tend to raise global temperatures, with some experts suggesting an event later this year could contribute to setting global heat records in 2027.
El Niño is characterized by warmer than usual ocean waters in the tropical Pacific and a weakening or reversal of easterly trade winds, which can keep cloud and rain away from Australia's east. The Bureau of Meteorology noted that while there is still disagreement among weather models, most show sea surface temperatures consistent with an El Niño could be in place by July.
Forecast Details
Caitlin Minney, a climatologist at the Bureau of Meteorology, stated that a developing El Niño is likely one of the factors behind the dry forecast. "May to July looks like rainfall will likely be below average for much of eastern Australia," she said. While drier conditions are expected to be concentrated in NSW and Queensland, the forecast also suggests parts of northern and western Victoria, southern South Australia, and the south-west of Western Australia could experience dryness.
The bureau is also monitoring conditions in the Indian Ocean, where some models suggest ocean temperatures to Australia's north-west could cool—another phenomenon that can reduce rainfall chances over the continent.
Historical Context and Expert Insights
Dr. Peter van Rensch, a climate scientist at Monash University, led a study on the effects of the El Niño-Southern Oscillation on Australian rainfall. He noted that El Niño's influence on Australian rainfall has historically been greatest in June, July, October, and November. "The pattern of the rainfall in the bureau's forecast does look similar to what we would expect from the historical relationship with El Niño," he said. However, he cautioned that while many models indicate a strong El Niño, much can change in the Pacific.
Despite some commentary about a potential "super El Niño," the bureau warned that forecasts at this time of year tend to be less reliable. The strength of an El Niño does not necessarily correlate with the strength of its impacts on Australian rainfall. Van Rensch added that the location of the warmest waters in the Pacific also influences impacts, with central Pacific El Niños typically having stronger effects on Australia.
Temperature Outlook
The bureau's long-range forecast also shows an increased chance of unusually high maximum temperatures from May to July across the bottom two-thirds of Australia. "The climate change signal is coming through very strongly in our temperature forecasts," said Minney. Global heating, driven by fossil fuel burning and deforestation, has warmed Australia by about 1.5°C since 1910.
