There are growing indications that a major climate driver may enter its wetter phase in the coming months, potentially increasing rainfall across large parts of Australia toward the end of winter.
The Bureau of Meteorology (BOM) has released its seasonal outlook, which suggests that winter temperatures are likely to be warmer than average—continuing a trend seen during the record-warm start to the year in southern Australia.
However, for many regions, rainfall is the key concern. While the east has suffered from recent floods, severe drought conditions persist in southern parts of the country.
Mixed Rainfall Outlook for Early Winter
The long-range forecast offers limited clarity for June and July. Models slightly favor wetter-than-average conditions for flood-affected areas of the east coast, parts of the interior, and northern Australia. However, regions such as southern Victoria, southwest Western Australia, and Tasmania are leaning toward drier conditions.
For much of Australia’s populated areas, rainfall predictions remain neutral, with no strong signal for either above- or below-average precipitation.
BOM’s national manager of climate services, Karl Braganza, explained, “The dice aren’t particularly loaded for wetter or drier conditions in the next three months.”
Stronger Rain Signal Later in Winter
Later in the season, from July to September, a clearer signal emerges, with a higher likelihood of above-average rainfall across much of the northern and central regions, as well as in Queensland, inland New South Wales, and South Australia.
Dr. Braganza attributed this shift to the Indian Ocean Dipole (IOD) potentially entering its negative, or “wet,” phase. Similar to El Niño and La Niña, the IOD influences Australia’s weather. In its negative phase, warmer waters near northwestern Australia create a moisture-rich atmosphere, which westerly winds can carry across the continent, enhancing rainfall potential.
He noted that consistently warm sea surface temperatures around Australia have already been influencing rainfall patterns, particularly in the east and inland.
Southern Regions in Need of Immediate Rain
In drought-hit areas like South Australia and western Victoria, the need for rain is critical. Agronomist Martin Colbert said crops may fail without immediate above-average rainfall: “If we get sub-average rainfall before spring, things will be that poor that — while rain will be nice — it won’t save us.”
Unfortunately, the forecast remains inconclusive for these areas even into the latter part of winter, offering little certainty for regions also experiencing increased fire risk due to prolonged dry conditions.
Warmer Temperatures Expected Nationwide
The forecast is clear about temperatures: Australia is expected to have another warmer-than-average winter. This trend has become common, with nine of the ten warmest winters on record occurring since 2010.
However, Dr. Braganza cautioned that warm averages don’t rule out cold snaps. For instance, last year’s record-breaking warm winter still included days with freezing temperatures.
Forecast Uncertainty Remains
The BOM’s long-range model captures large-scale climate trends but cannot predict individual weather systems, which can significantly affect seasonal rainfall outcomes.
Chiara Holgate, a hydro-climate scientist from the Australian National University, emphasized that a small number of intense rain events—just 10 heavy rainfall days—can be the difference between a wet or dry season.
“If we didn’t get those 10 or so heavy rain days, then that region would be at risk of entering drought,” she said.
