Climate and Oceans Support Program in the Pacific (COSPPac) Bulletin

Issued 30 January 2026

• La Niña continues in the tropical Pacific.
• The Madden Julian Oscillation (MJO) has continued to strengthen in the Western Pacific and likely to weaken while progressing eastwards across the Western Pacific.
• In December, the Intertropical Convergence Zone (ITCZ) was active and shifted north of its normal position over the northern Pacific. The South Pacific Convergence zone was active and shifted south to its normal position especially over Fiji and Tonga region.
• Sea surface temperatures (SSTs) for December 2025 were near-normal to below-normal in the central and eastern Pacific, while above-normal in the western Pacific.
• The Coral bleaching alert on 22 January shows a few patches of 'Alert Level 1' over part of southern Tonga, Samoa, PNG, and Wallis &Futuna.
• For January to March 2026, the models agree that above normal rainfall is likely or very likely over CNMI, Guam, southeast FSM, northern and southern RMI, and a band stretching southeastwards over PNG, southern Solomon Islands, New Caledonia, Vanuatu, eastern Fiji, southern Tonga, and Niue. Below normal rainfall is likely or very likely in a band stretching southeastwards from Kiribati (Phoenix, and Line Islands), Tokelau, northern Cook Island, and northern French Polynesia.
• The weekly tropical cyclone forecasts from the ACCESS-S model shows increased risks for Solomon Islands, New Caledonia, Vanuatu, Fiji, and Tonga, for the 31 January to 06 February.