Monthly Archives: February 2026

February 26, 2026

Subseasonal Weather Outlook (2 – 15 March 2026)

Issued: 26 February 2026
First forecast week: 2 – 8 March 2026
Second forecast week: 9 – 15 March 2026

Figure 1: Rainfall Outlook

Figure 2: Temperature Outlook

Over most of the central and eastern equatorial region in Week 1 (2 – 8 March), drier than usual conditions for this time of the year are predicted, along with warmer than usual temperatures.

Over much of the northeastern Maritime Continent in Week 2 (9 – 15 March), wetter than usual conditions are predicted.

Over much of Mainland Southeast Asia in Week 1 (2 – 8 March), cooler than usual temperatures are predicted to develop. These cooler conditions are likely to persist in Week 2 (9 – 15 March).

There was no discernible Madden-Julian Oscillation (MJO) signal towards the end of February, based on the RMM index. Most models predict no significant MJO activity during the forecast period (2 – 15 March), although a few models predict the development of an MJO signal in the Maritime Continent (Phase 5) during Week 1 (2 – 8 March).

The outlook is assessed for the region in general, where conditions are relative to the average conditions for the corresponding time of year. For specific updates on the national scale, the relevant ASEAN National Meteorological and Hydrological Services should be consulted.

February 20, 2026

Review of Regional Weather for January 2026

1. Overview

1.1 During January 2026, below- to near-average rainfall was recorded over much of the Maritime Continent with near-average rainfall over Mainland Southeast Asia (Figure 1). For the Maritime Continent, most of the equatorial region recorded below-average (drier) anomalies, with scattered spots of near- to above-average (wetter) anomalies for the southern and northeastern regions for both datasets (GSMaP-NRT and CMORPH-CRT). There were no notable anomalies over Mainland Southeast Asia, in line with the current dry season. The largest positive (wetter) anomalies were recorded over central Philippines, with the largest negative (drier) anomalies over western Borneo.

1.2 The observed rainfall anomaly pattern of below-average rainfall over much of the equatorial region and the above-average rainfall over northeast Maritime Continent is consistent with the predictions from the subseasonal weather outlooks for January 2025 (22 December 2025 – 4 January 2026, 5 – 18 January 2025, and 19 January – 1 February 2026). The observations match the most likely tercile from the seasonal outlook for January 2026 for central and northeastern Maritime Continent where the rainfall observed the largest drier and wetter anomalies, but differ for much of the rest of the Maritime Continent.

Figure 1: Rainfall anomalies for January 2026 based on GSMaP-NRT data (left) and CPC CMORPH-CRT data (right). The climatological reference period is 2001-2024. Green colour denotes above-average rainfall (wetter), while orange denotes below-average rainfall (drier).

1.3 Above-average temperature was recorded over the eastern Maritime Continent and parts of northern Mainland Southeast Asia, while below-average temperature was recorded over central and southern Mainland Southeast Asia, with near-average temperature for much of the rest of Southeast Asia (Figure 2). The warmest anomalies (1°C – 2°C above average) were recorded over western Myanmar, while the coolest anomalies (1°C – 2°C below average) were recorded over Cambodia, southern Viet Nam and central Thailand.

Figure 2: Temperature anomalies for January 2026 based on ERA-5 reanalysis. The climatological reference period is 2001-2024. Red colour denotes above-average temperature (warmer), while blue denotes below-average temperature (colder).

2. Climate Drivers

2.1 At the start of January, the Madden-Julian Oscillation (MJO) was inactive based on the RMM diagram (Figure 3). The signal emerged over the Western Pacific (Phase 6) in Week 2, strengthening with little eastward propagation in Phase 6 until middle of Week 3 when it weakened slightly and started again propagating eastwards. By Week 4, the MJO signal was in Phase 7 of the Western Pacific where it stalled and weakened at the end of the month. At this time of the year, Phases 6 and 7 tend to bring drier conditions to the western and southern Maritime Continent, in line with the observed rainfall in January also showing drier conditions for much of the Maritime Continent.

Figure 3: The MJO phase diagram. The diagram illustrates the movement of the MJO through different phases, which correspond to different locations along the equator (denoted in the text with the first day of the month in blue and the last day of the month in red). The distance of the index from the centre of the diagram is related to the strength of the MJO. Values within the grey circle are considered weak or indiscernible (data from the Bureau of Meteorology, Australia).

2.2 La Niña conditions persisted in January 2026, although key atmospheric indicators show signs of the La Niña conditions weakening. La Niña events tend to bring wetter-than-average conditions to much of the Maritime Continent during this time of the year. The Indian Ocean Dipole (IOD) is currently in the neutral state.

February 16, 2026

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.

Figure 1: Average Daily Rainfall and Mean Winds for January 2026. (Source: JAXA GsMaP and GFS, respectively)

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).

Figure 2: Hotspot counts for the northern ASEAN region for January (2022-2026) based on NOAA-20 satellite surveillance.

Figure 3: Hotspot counts for the southern ASEAN region for January (2022-2026) based on NOAA-20 satellite surveillance.

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).

Figure 4: Distribution of hotspots detected in January 2026 based on NOAA-20 satellite surveillance.

Figure 5: Maximum fire intensity in January 2026 based on NOAA-20 satellite surveillance.

Figure 6: Number of days with moderate to dense smoke haze observed in January 2026 based on satellite imagery, ground observations, and air quality reports.

Figure 7: Slight to moderate localized smoke plumes observed over the northern and eastern parts of Cambodia, as well as the southern parts of Viet Nam on 9 January 2026. (Source: Himawari-9 satellite surveillance)

Figure 8: Slight to moderate localized smoke plumes observed over the northern parts of Viet Nam on 14 January 2026. (Source: Himawari-9 satellite surveillance)

Figure 9: Slight to moderate localized smoke plumes observed over the central parts of Myanmar on 23 January 2026. (Source: Himawari-9 satellite surveillance)

Figure 10: A moderate smoke plume observed over the eastern parts of Johor on 31 January 2026. (Source: Himawari-9 satellite surveillance)

February 11, 2026

Subseasonal Weather Outlook (16 February – 1 March 2026)

Issued: 11 February 2026
First forecast week: 16 – 22 February 2026
Second forecast week: 23 February – 1 March 2026

Figure 1: Rainfall Outlook

Figure 2: Temperature Outlook

Wetter conditions are predicted over parts of western and central Mainland Southeast Asia as well as parts of the northwestern Maritime Continent in Week 1 (16 – 22 February). Wetter conditions are predicted over parts of the northeastern Maritime Continent in the next fortnight (16 February – 1 March).

Drier than usual conditions for this time of the year are predicted over much of the western and central equatorial region in Week 2 (23 February – 1 March).

No significant regional temperature anomalies are predicted in the next fortnight (16 February – 1 March).

A Madden-Julian Oscillation (MJO) signal was present over the Indian Ocean (Phases 2 and 3) towards the middle of February 2026, based on the RMM index. Most models predict the signal to propagate eastwards towards the Maritime Continent (Phase 4) in Week 1 (16 – 22 February), with no significant MJO activity in Week 2 (23 February – 1 March).

February 2, 2026

Alert20260202 – Activation of Alert Level 2 for the Mekong sub-region

Activation of Alert Level 2 for the Mekong sub-region

Under the ongoing dry weather conditions over the Mekong sub-region, the hotspot and smoke haze situation has been intensifying in recent weeks. A total of 608 and 531 hotspots were detected in the Mekong sub-region on 31 January and 1 February 2026 respectively from the NOAA-20 satellite. Based on satellite surveillance, scattered hotspots were detected in Cambodia while isolated hotspots were detected elsewhere in the sub-region. Moderate to dense smoke haze was observed in various parts of Cambodia, northern parts of Myanmar, central parts of Thailand, and the southern parts of Lao PDR.

In the coming weeks, the prevailing winds are forecast to continue blowing mostly from the northeast or east, and the dry weather conditions are expected to continue. Under these conditions, the hotspot and smoke haze situation could worsen, increasing the risk of transboundary smoke haze occurrence over the Mekong sub-region.