Category Archives: Haze Review

Review of Regional Haze Situation for February 2026

1.1 During February 2026, Northeast monsoon conditions were predominantly observed over the ASEAN region. While the prevailing winds blew mostly from the northeast or northwest over the region, the Mekong sub-region occasionally experienced days with prevailing light and variable winds. (Figure 1)

1.2 Extensive dry conditions were generally observed over the Mekong sub-region as well as the northern parts of the Philippines during the month of February 2026, though there were some showers observed over the southeastern and central parts of the Mekong sub-region on a few days during the last week of February. Parts of Peninsular Malaysia and Sumatra also experienced days with relatively lower rainfall during the month (Figure 1). Heavier showers were observed over the Philippines, which can be attributed to Tropical Storm Penha. To reflect the ongoing and expected dry weather conditions over the Mekong sub-region, ASMC issued Alert Level 2 for the Mekong sub-region on 2 February 2026.

1.3 Despite the drier conditions, hotspot counts over the ASEAN region for February 2026 were observed to be much lower or comparable compared to the hotspot counts from the preceding years (2022-2025).

1.4 Scattered to widespread hotspots were often observed over the northern and western parts of Cambodia as well as the southern parts of Lao PDR (Figure 4), leading to moderate to dense smoke plumes observed over these areas for many days during February 2026 (Figure 6). Transboundary smoke haze would occasionally occur from the southern parts of Lao PDR to the northern parts of Cambodia, as well as from the western parts of Cambodia to the central parts of Thailand (Figure 8 & 9) . Moderate to dense smoke haze was observed to persist over the central and northern parts of Myanmar under the prevailing light winds situation (Figure 6 and 9 ). In the southern ASEAN region, Smoke plumes were also observed in the southern parts of Peninsular Malaysia, the central parts of Sumatra and in West Kalimantan for a few days in the month. (Figure 6 and 7 )

Review of Regional Haze Situation for January 2026

1.1 The Northeast Monsoon continued over the ASEAN region throughout January 2026. The prevailing low-level winds over regions north of the Equator blew mainly from the northeast to east, except over the northern parts of the Mekong sub-region where the winds were light and variable in direction (Figure 1). Over regions south of the Equator, the prevailing low-level winds blew mainly from the west to north (Figure 1).

1.2 Dry weather persisted over the Mekong sub-region, Peninsular Malaysia and the northern parts of the Philippines in January 2026. Showers were observed elsewhere in the ASEAN region (Figure 1), with the areas south of the Equator, the eastern parts of Borneo and the central parts of the Philippines experiencing higher rainfall. The latter was due to the influence of Tropical Storm NOKAEN.

1.3 The hotspot counts over the northern ASEAN region were generally lower than or comparable to those recorded in the same month during previous years (Figure 2). Over the southern ASEAN region, the hotspot counts were mostly higher compared to previous years, especially over Kalimantan and Sumatra, where there was a significant increase in hotspot activity, with the highest count recorded in five years (Figure 3).

1.4 Persistent and intense hotspots were detected mostly in Cambodia, Myanmar and the southern parts of Lao PDR (Figures 4 and 5). During prolonged periods of dry weather, moderate and persistent smoke plumes were observed mainly over the central parts of Myanmar and the northern parts of Cambodia. Smoke plumes were also observed over the other parts of the Mekong sub-region, Sumatra, Peninsular Malaysia and Kalimantan (Figures 6 to 10).

Review of Regional Haze Situation for December 2025

1.1 In December 2025, Northeast monsoon was well established over the ASEAN region as the prevailing low-level winds over most areas north of the Equator blew from the northeast or east except for the northern parts of the Mekong sub-region where the prevailing low-level winds were light and variable in direction. Over the areas south of the Equator, the prevailing low-level winds blew mainly from the west and northwest. (Figure 1).

1.2 Dry conditions were observed over most parts of the Mekong sub-region except for the coastal areas in the southern parts of Viet Nam where some showers were observed (Figure 1). In view of the expected persistence of the dry weather conditions across the sub-region, the Alert Level was activated to Level 1 for the northern ASEAN region, on 26 December 2025, to signal the start of its dry season. Wet weather was observed over the rest of the ASEAN region with intense rainfall recorded over the eastern parts of Peninsular Malaysia (Figure 1). Heavy rainfall was also recorded in the eastern parts of the Philippines (Figure 1) under the influence of Tropical Cyclone WILMA.

1.3 The overall hotspot counts in December 2025 over the ASEAN region were generally lower than or comparable to previous years.

1.4 During the review period, isolated to scattered hotspots were detected in the Mekong sub-region (Figures 4 and 5). While most of the hotspots were short-lived, some hotspots in the central parts of Myanmar and Thailand, as well as parts of Cambodia, were persistent and intense. Moderate smoke plumes were observed to emanate from a few hotspots in the southeastern parts of Cambodia and in the southern parts of Viet Nam (Figures 6 and 7). A few slight localised smoke plumes were also observed to emanate from some hotspots detected in the Mekong sub-region. Although a few to isolated hotspots were detected in Sumatra and Kalimantan, the hotspot activities were generally subdued over the southern ASEAN region (Figure 4 and 5).

Review of Regional Haze Situation for November 2025

1.1 In November 2025, the inter-monsoon conditions gradually gave way to the Northeast Monsoon conditions over the ASEAN region as the prevailing winds were observed to blow from the northeast or east over most parts of the northern ASEAN region. However, light and variable prevailing winds were still observed to persist in most parts of the southern ASEAN region.

1.2 Dry conditions emerged over parts of the Mekong sub-region in November 2025 except for wet weather observed over the central and southern parts of Viet Nam. Increased rainfall amounts in Viet Nam and the Philippines were attributed to heavy showers caused by Typhoon Kalmaegi and Typhoon Fung-wong.

1.3 Widespread wet weather was observed to persist over the southern ASEAN region in November 2025. Heavier showers were also observed in the southern parts of Thailand and the northern parts of Sumatra due to Tropical Cyclone Senyar. Floods and landslides were reported in parts of Peninsular Malaysia, Indonesia and Thailand, leading to loss of lives and infrastructure damage.

1.4 The hotspot counts for the ASEAN region in November 2025 were lower than or comparable to the previous years (Figure 2 and 3).

1.5 For the southern ASEAN region, isolated hotspots were detected in Sumatra and Borneo, with localised smoke plumes observed in parts of Kalimantan, Sabah and Sumatra on a few days. For the northern ASEAN region, a few to isolated hotspots were detected in many parts of the Mekong sub-region. Moderate smoke plumes were observed in the northern parts of Viet Nam on 24 November 2025 (Figure 6 and 7) and localised smoke plumes were observed emanating from isolated hotspots in parts of Myanmar, Thailand, Viet Nam and Lao PDR.

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).

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).

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).

Review of Regional Haze Situation for September 2025

1.1 Southwest monsoon conditions persisted over the ASEAN region in September 2025. The prevailing low-level winds blew mainly from the southeast over areas south of the Equator and turned to blow from the southwest or west over areas north of the Equator (Figure 1).

1.2 While Java and the Lesser Sunda Islands continued to face drier conditions, showers were prevalent over the rest of the ASEAN region. There were three notable tropical cyclones during the review period, namely Tropical Storm Mitag , Super Typhoon Ragasa and Typhoon Bualoi, which developed one after another in September. Heavy rains and strong winds brought by the storms affected several areas in the northern ASEAN region, particularly the Philippines and the eastern parts of the Mekong sub-region, where several floods and landslides were reported.

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

1.4 Isolated to scattered hotspots were detected in most parts of the southern ASEAN region, with persistent hotspot clusters detected in West Kalimantan, the southern parts of Sumatra, and the Lesser Sunda Islands (Figure 4). Hotspots were also detected as particularly intense in West Kalimantan and the Lesser Sunda Islands. Moderate smoke plumes were seen originating from hotspots in West and Central Kalimantan, with plumes from West Kalimantan occasionally drifting into western Sarawak (Figures 6 and 7). Slight localised smoke plumes were also noted in southern Sumatra on certain days. With the exception of isolated hotspots detected in parts of Viet Nam, hotspot and smoke haze activity over the northern ASEAN region remained subdued under the prevailing wet weather (Figure 4).

Review of Regional Haze Situation for August 2025

1.1 The ASEAN region experienced Southwest Monsoon conditions during August 2025, characterized by prevailing southeasterly or southwesterly winds in the southern ASEAN region and southwesterly or westerly winds in the northern ASEAN region (Figure 1).

1.2 1.2 While Java and the Lesser Sunda Islands continued to face drier conditions, showers were prevalent over the rest of the southern ASEAN region. Alert Level 2 was downgraded to Level 1 for the southern ASEAN region on 12 August 2025 due to the expected improvement of the hotspot and haze situation, and the reduced risk of transboundary haze over the region under the wet weather conditions. In the northern ASEAN region, wet weather continued, particularly over the northern parts of the Philippines and the eastern parts of Mekong sub-region where there was intense rainfall brought by Typhoons Kajiki and Nongfa (Figure 1).

1.3 1.3 The hotspot counts for the ASEAN region in August 2025 were mostly comparable to the same month in previous years (Figures 2 and 3).

1.4 Isolated to scattered hotspots were detected in most parts of the southern ASEAN region, with persistent hotspot clusters detected in West Kalimantan, the northern and central parts of Sumatra, and the Lesser Sunda Islands (Figure 4). Moderate but localised smoke plumes were observed to emanate from hotspots in West Kalimantan and the northern parts of Sumatra on some days (Figures 6 and 7).

1.5 In the northern ASEAN region, the hotspot counts remained low with no significant smoke plumes were observed during the month (Figures 4 and 6).

Review of Regional Haze Situation for July 2025

1.1 Southwest Monsoon conditions persisted over the ASEAN region throughout July 2025. The prevailing winds over the northern ASEAN region blew from the southwest to west. Over the southern ASEAN region, the prevailing winds blew mostly from the southeast to south, except for the winds over the equatorial region which were light and variable in direction (Figure 1).

1.2 Showers were observed over the southern ASEAN region during the first half of July 2025, apart from Java and the Lesser Sunda Islands where it was dry (Figure 1). During the latter half of the review period, dry weather was observed over parts of Kalimantan, Peninsular Malaysia and Sumatra. On 19 July 2025, the Alert Level 2 for the southern ASEAN region was activated due to an escalation of hotspot and smoke haze activities and heightened risk of transboundary smoke haze occurrences in the region. In contrast, the northern ASEAN region experienced wet weather in July 2025, with heavy precipitation recorded over the northern parts of the Philippines due to the influence of Typhoon CO-MAY and Tropical Cyclone WIPHA.

1.3 There was a rise in hotspot activity over the southern ASEAN region due to periods of drier conditions, with hotspot counts higher or comparable to previous years (Figure 2). Notably, Sumatra saw the highest hotspot count over the last 5 years. The hotspot counts for the northern ASEAN region were lower or comparable to the past few years (Figure 3).

1.4 During the latter half of July 2025, there was an increase in hotspot activities in most of the southern ASEAN region, particularly over the western parts of Kalimantan and the central parts of Sumatra where more intense and persistent fires were observed (Figure 4). Slight to moderate smoke plumes were observed over parts of Borneo, Sumatra and Peninsular Malaysia, with transboundary smoke haze observed to drift from the central parts of Sumatra into Peninsular Malaysia and from the western parts of Kalimantan into Sarawak (Figure 6, 7, 8). The hotspot activity over the northern ASEAN region remained subdued under the prevailing wet weather (Figure 4).

Review of Regional Haze Situation for June 2025

1.1 Southwest Monsoon conditions became fully established over the ASEAN region in June 2025. Over much of the southern ASEAN region, the prevailing winds blew mainly from the southeast. The prevailing winds over the Mekong sub-region were mostly southwesterly or westerly while the regions close to the Equator and the Philippines experienced winds that were mostly light and variable in direction (Figure 1).

1.2 Rainy weather prevailed over most parts of the ASEAN region during the review period. In particular, moderate to heavy showers fell on several days over the central parts of Viet Nam under the influence of Typhoon WUTIP. The resulting flooding and landslides were reported across multiple areas in the central parts of Viet Nam . In contrast, drier conditions were observed over Sumatra, Java and the Lesser Sunda Islands (Figure 1). In view of the expected continuation of the dry weather, Alert Level 1 for the southern ASEAN region was activated on 12 June 2025.

1.3 Hotspot activity in the northern ASEAN region was mostly subdued in June 2025 due to the prevailing wet weather conditions. The total number of hotspots were lower or comparable to the same period of previous years (Figure 2). Meanwhile, hotspot counts in the southern ASEAN region were generally comparable to previous years except for Sumatra which recorded the highest number of hotspots in five years (Figure 3).

1.4 In June 2025, a few to isolated hotspots were detected in the ASEAN region, particularly in the northern and central parts of Sumatra, as well as parts of Viet Nam where the fires were more persistent and intense. Slight localised smoke plumes were observed emanating from hotspots in West Kalimantan, Sarawak and the northern and central parts of Sumatra on some days (Figure 4, 5 and Figure 6).

Review of Regional Haze Situation for May 2025

1.1 Inter-monsoon conditions prevailed throughout the ASEAN region during May 2025, characterised by light winds that varied in direction across most parts of the region (Figure 1).

1.2 Wet weather dominated over most parts of the ASEAN region as the monsoon rainband continued to shift northwards from the Equator, with the northern ASEAN region experiencing increased amounts of rainfall compared to previous months. Due to the expected persistent shower activities over the Mekong sub-region, the Alert Level was downgraded from Alert Level 2 to 1 on 13 May 2025, and subsequently from Alert level 1 to 0 on 21 May 2025, signalling the end of the dry season for the sub-region. While showers persisted over most areas in the southern ASEAN region this month, drier conditions were observed over parts of Sumatra and Kalimantan for a few days (Figure 1).

1.3 The hotspot counts for the ASEAN region for May 2025 were comparable to those recorded in May of previous years (Figure 2 & 3).

1.4 Isolated to scattered hotspots were detected over most parts of the Mekong sub-region, especially over the northern parts of Lao PDR where intense and persistent hotspot clusters were observed (Figure 4 and 5). Moderate to dense transboundary smoke haze was also observed to drift eastwards from the northern parts of Lao PDR into the northern parts of Viet Nam on a few days (Figure 6 and 7).

1.5 1.5 Over the southern ASEAN region, the hotspot and smoke haze situation remained mostly subdued. However, there were a few days when slight localized smoke plumes were observed emanating from hotspots in the central parts of Sumatra, the western parts of Kalimantan and Sarawak (Figure 4, 5 and 8).