Temperature
Monthly Temperature Outlook: September 2025
Issued: 2 Sep 2025
For September 2025, above-normal temperature is predicted over Southeast Asia.
For September 2025, above-normal temperature is predicted over Southeast Asia (Figure 1). The likelihood of above-normal temperature is high, apart from over the northern half of Mainland Southeast Asia and parts of the central Maritime Continent. Most of the models (more than six models, Figure 2) predict above-normal temperature as the most likely tercile, apart from over parts of the central Maritime Continent. Model skill for predicting above-normal temperature is relatively good for most of Southeast Asia.
Figure 1: Temperature tercile summary predictions of the multi model ensemble for September 2025 (contains modified Copernicus C3S information).
Figure 2: Number of models in agreement in the multi-model ensemble for the dominant tercile for September 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 Sep 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.