Rainfall
Seasonal Rainfall Outlook: November 2025 - January 2026 (NDJ)
Issued: 24 Oct 2025
For NDJ 2025-2026, models predict above-normal rainfall over much of the southern and eastern Maritime Continent and southern Mainland Southeast Asia.
For NDJ 2025-2026, above-normal rainfall is predicted for much of the southern and eastern Maritime Continent, based on the multi-model ensemble (Figure 1). The highest probability of above-normal rainfall is over the southern Maritime Continent. Elsewhere in the Maritime Continent, below-normal rainfall is predicted over parts of the northwestern and central Maritime Continent. Most models agree on above-normal rainfall as the most likely tercile for the southern and eastern parts of the region (more than six models, Figure 2). For below-normal rainfall, a mix of some models (4 – 6) and most models (more than six models) agree with each other.
For Mainland Southeast Asia, above-normal rainfall is predicted over the southern and western regions. Most models agree on above-normal rainfall over the southeastern portion (more than 6 models), with some models (4 – 6 models) agreeing for the rest of the mentioned area. Mix of below-normal rainfall and no dominant tercile is predicted for most of northern Mainland Southeast Asia.
Model skill for predicting above-normal rainfall is good for the southern and eastern Maritime Continent and southeastern Mainland Southeast Asia. Model skill is poor to moderate elsewhere in the region.
Figure 1: Rainfall tercile summary predictions of the multi model ensemble for NDJ 2025-2025 (contains modified Copernicus C3S information).
Figure 2: Number of models in agreement in the multi-model ensemble for the dominant tercile for SON 2025. Where there is no dominant tercile, it refers to the number of models with near-normal tercile (contains modified Copernicus C3S information).
Figure 3: Average climatological rainfall's lower tercile boundary for NDJ based on CHIRPS (Reference period: 1991-2020).
Figure 4: Average climatological rainfall's upper tercile boundary for NDJ based on CHIRPS (Reference period: 1991-2020).
The qualitative outlook is assessed for the region in general. For specific updates on the national scale, the relevant ASEAN National Meteorological and Hydrological Services should be consulted.