Assessment of rainfall for September 2023 showed that rainfall anomalies in most parts of the ASEAN region are within the near-normal range (50 to -50 mm). However, positive rainfall anomalies were observed over the southwestern Philippines, central Thailand, northeastern Laos, southern Myanmar, eastern to southeastern Cambodia, the central and southern parts of Vietnam, and in northeastern part of the Sumatra island in Indonesia.

Furthermore, the northern to northeastern parts of Myanmar, northern Vietnam, the northeastern to eastern Philippines, and most parts of Indonesia are within the negative rainfall anomalies.