Overview

• The IOD index has dipped to -0.6°C for two consecutive weeks, falling below the -0.4°C threshold that defines a negative phase.
• Models from the Bureau of Meteorology forecast the negative IOD will intensify through early spring and persist until December, potentially marking the first full negative phase year since 2022.
• Seasonal outlooks assign a 70 to 80 percent chance of above-median rainfall across most of central and eastern Australia, paralleling historical trends of wetter winters and springs.
• Prolonged wet conditions could relieve drought in South Australia but heighten flood risks in already waterlogged areas of New South Wales and Queensland.
• Cloud cover linked to the IOD is projected to suppress daytime highs through November, and some Pacific forecasts indicate a possible La Niña that could amplify rainfall.