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Australia’s Six-Month Outlook: December 2025 – June 2026 How Climate Drivers and High-Energy Periods Shape the Season Ahead

While mainstream guidance expected a widespread wet spring, OIF’s caution of a drier-leaning start to spring has proven accurate, highlighting the value of including non-traditional drivers beyond ocean indices in seasonal risk assessments.

Australia's climate history is marked by recurring droughts, significantly influenced by its geographical position within the subtropical high-pressure belt. This region is characterised by descending, dry, and stable air masses, resulting in generally low and erratic rainfall across much of the continent. While the far north and south benefit from relatively regular rain-bearing systems, and the east coast is fed by moisture-laden winds from the Tasman and Coral Seas, large

December marks the beginning of summer in Australia and a pivotal point in the nation’s annual climate cycle. It is a month of atmospheric transition, as southern synoptic patterns give way to the intensifying influence of tropical systems in the north. This combination of subtropical heat, humid tropical air masses, and retreating mid-latitude systems creates significant variability in rainfall, temperature, and severe weather outcomes across the continent.

Upcoming Rainfall Outlook – Long Range Update 🌧️ The next significant weather period in the long-range forecast falls between 21st and 25th April, with increased rainfall potential across southwest WA. This event will likely be associated with Ex-TC Errol interacting with an approaching cold front and upper-level trough pushing up from the Southern Ocean.