Review of Regional Haze Situation for October 2025

1.1 The Southwest Monsoon transitioned to the inter-monsoon conditions during October 2025, with the monsoon rainband shifted towards the Equator. This was characterised by light low-level winds with variable directions over most of the ASEAN region in October (Figure 1). The South China Sea and the northern parts of the Philippines experienced strong winds at times, influenced by Typhoon Matmo and Tropical Storm Fengshen (Figures 9 and 10).

1.2 Showers prevailed over most of the ASEAN region in October 2025 (Figure 1). With increased shower activities, the Alert Level for the Southern ASEAN region was downgraded from Level 1 to Level 0 on 22 October 2025, marking the end of the dry season for the region. Heavy rainfall was observed over the Philippines and the central parts of Viet Nam due to Typhoon Matmo and Tropical Storm Fengshen (Figures 9 and 10).

Figure 1: Average Daily Rainfall and Mean Winds for October 2025. (Source: JAXA GsMaP and GFS, respectively)

1.3 In October 2025, the hotspot counts for the ASEAN region were generally lower than or comparable to those recorded in the same month during previous years (Figure 2 and 3).

Figure 2: Hotspot counts for the southern ASEAN region for October (2021-2025) based on NOAA-20 satellite surveillance.

Figure 3: Hotspot counts for the northern ASEAN region for October (2021-2025) based on NOAA-20 satellite surveillance.

1.4 Persistent and intense hotspots were detected mostly in the central and southern parts of Sumatra, the central and eastern parts of Kalimantan and parts of Sulawesi and the Lesser Sunda Islands (Figures 4 and 5). Slight to moderate localised smoke plumes were observed over the central and southern parts of Sumatra and the eastern parts of Kalimantan during brief periods of dry weather (Figures 6, 7 and 8).

Figure 4: Distribution of hotspots detected in October 2025 based on NOAA-20 satellite surveillance.

Figure 5: Maximum fire intensity in October 2025 based on NOAA-20 satellite surveillance.

Figure 6: Number of days with moderate to dense smoke haze observed in October 2025 based on satellite imagery, ground observations, and air quality reports.

Figure 7: Slight to moderate localised smoke plumes observed over the eastern parts of Kalimantan on 15 October 2025. (Source: Himawari-9 satellite surveillance)

Figure 8: Slight to moderate localised smoke plumes were observed over the central and southern parts of Sumatra on 31 October 2025. (Source: Himawari-9 satellite surveillance)

Figure 9: Typhoon Matmo over the northern parts of the South China Sea (Source: NOAA-21 satellite surveillance)

Figure 10: Tropical Storm Fengshen over the South China Sea (Source: NOAA-20 satellite surveillance)