Rainfall
Seasonal Rainfall Outlook: May-July 2026 (MJJ)
For MJJ 2026, below-normal rainfall is predicted for the southern ASEAN region.
For MJJ 2026, an increased chance of below-normal rainfall is predicted for the southern ASEAN region, based on the multi-model ensemble (Figure 1). Most models (more than six models) agree with below-normal as the dominant tercile for much of the region, apart from over parts of the equatorial regions where only some models (4 – 6 models) agree. Model skill is moderate to good over the eastern half of the southern ASEAN region and low to moderate over the western half at this time of the year.
For the northern ASEAN region, no dominant tercile is predicted for much of the region, apart from some models (4 – 6 models) in agreement regarding an increase in chance of above-normal rainfall over the northeastern part. Model skill is low for the northernmost part of the northern ASEAN region, and low to moderate elsewhere at this time of the year.
Figure 1: Rainfall tercile summary predictions of the multi model ensemble for MJJ 2026 (contains modified Copernicus C3S information).
Figure 2: Number of models in agreement in the multi-model ensemble for the dominant tercile for AMJ 2026. 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 MJJ based on CHIRPS (Reference period: 1991-2020).
Figure 4: Average climatological rainfall's upper tercile boundary for MJJ 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.