Temperature
Seasonal Temperature Outlook: September-November 2025 (SON)
Issued: 2 Sep 2025
For SON 2025, above-normal temperature is predicted over much of Southeast Asia.
For SON 2025, above-normal temperature is predicted over most of Southeast Asia (Figure 1). Where above-normal temperature is predicted, most models (more than six models, Figure 2) predict above-normal temperature as the most likely tercile. Over parts of central and eastern Mainland Southeast Asia and the central Maritime Continent, either no dominant or near-normal temperature is predicted. There is less agreement between models for these regions, with only some models (4 – 6) predicting near-normal temperature. Model skill for predicting above-normal temperature is good for most of Southeast Asia.
Figure 1: Temperature tercile summary predictions of the multi model ensemble for SON 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 temperature for SON based on ERA5 (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.