Australia edges closer to southern hemisphere winter, yet recent weather feels like lingering summer. April delivered unseasonably high temperatures and scant rainfall nationwide, with many areas recording above-average or very much above-average heat.
New South Wales logged its second-driest April on record. In Victoria’s usually rainy Gippsland region, Bairnsdale received just 5.4mm of rain—the lowest amount since 1943.
Shifting Weather Patterns
This dry spell contrasts sharply with the heavy rains of February and March. A tropical low-pressure system stalled over central Australia in late February, sparking widespread downpours. Kati Thanda-Lake Eyre filled for the second time in two years, and desert vegetation flourished rapidly.
April brought persistent high-pressure systems over eastern Australia. Descending air in these systems prevents cloud formation, leading to clear, sunny days and warm conditions. Without clouds at night, heat escapes quickly into space, resulting in cooler mornings, lower minimum temperatures, and occasional fog in the east.
These high-pressure ridges blocked cold fronts from the west, diverting them southward near the Great Australian Bight and bypassing eastern states.
Climate Change Amplifies the Heat
High-pressure systems alone do not explain the warmth. The past 13 autumns feature daily maximum temperatures exceeding the 1961–90 baseline average across Australia.
Climate records show Australian air temperatures have risen 1.51°C since 1910, driven by greenhouse gas emissions from fossil fuels. Global warming strengthens the subtropical ridge—a band of high pressure around 30°S latitude, spanning from Perth to Sydney—that deflects cold fronts during summer and autumn.
Researchers anticipate this intensified ridge will cut autumn and winter rainfall in southern Australia.
El Niño on the Horizon
Speculation surrounds a potential strong El Niño this year, but conditions remain neutral in the Pacific, with neither El Niño nor La Niña dominant. Warmer subsurface ocean waters signal possible development by late winter, though strength and duration stay uncertain.
El Niño typically warms eastern Australia and reduces winter-spring rainfall by weakening trade winds and limiting rain-bearing systems. Major droughts have coincided with past events.
Outlook for Winter
The subtropical ridge shifts north in winter, allowing more cold fronts to reach southern Australia and boosting rainfall in the south. However, an emerging El Niño could suppress precipitation.
The Bureau of Meteorology’s long-range forecast, factoring in cold front winds, El Niño, and the Indian Ocean Dipole, predicts a warmer-than-average winter nationwide.
May rainfall outlook shows below-average levels across most regions, except normal amounts in southern Victoria, southwest Tasmania, and central Western Australia. Northern Queensland may see above-normal rain.
From June to August, drier conditions are likely in southwest and southeast Australia, while northern Queensland, northeast Northern Territory, and central Western Australia face higher chances of wetter weather.
Longer-term forecasts carry more uncertainty, so farmers, fire managers, and others relying on rain should monitor updates frequently.
