Subseasonal Weather Outlook and Review

Warmer than usual temperature is predicted in Week 1 (22 – 28 Dec 2025) over much of the eastern and southern Maritime Continent.

Drier than usual conditions for this time of the year are predicted​ over parts of the western Maritime Continent and southern Mainland Southeast Asia in Week 2 (29 Dec 2025 – 4 Jan 2026).
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There was no Madden-Julian Oscillation (MJO) signal present by the middle of December 2025, based on the RMM Index. Most models predict no sustained MJO signal during the forecast period (22 Dec 2025 – 4 Jan 2026).

The outlook is assessed for the region in general, where conditions are relative to the average conditions for the corresponding time of year. For specific updates on the national scale, the relevant ASEAN National Meteorological and Hydrological Services should be consulted.

Warmer than usual temperature is predicted in Week 1 (22 – 28 Dec 2025) over much of the eastern and southern Maritime Continent.

Drier than usual conditions for this time of the year are predicted​ over parts of the western Maritime Continent and southern Mainland Southeast Asia in Week 2 (29 Dec 2025 – 4 Jan 2026).
​​
There was no Madden-Julian Oscillation (MJO) signal present by the middle of December 2025, based on the RMM Index. Most models predict no sustained MJO signal during the forecast period (22 Dec 2025 – 4 Jan 2026).

The outlook is assessed for the region in general, where conditions are relative to the average conditions for the corresponding time of year. For specific updates on the national scale, the relevant ASEAN National Meteorological and Hydrological Services should be consulted.