Source: Government of Singapore
Higher risk of transboundary haze affecting Singapore
29 May 2026 – The Meteorological Service Singapore (MSS) has forecast El Niño1 conditions to develop in June to July 2026. A positive Indian Ocean Dipole (IOD)2 is also predicted to develop in the second half of the year. Both climate phenomena are expected to bring warmer and drier conditions to Singapore and the surrounding region from June to October 2026, and this will increase the risk of transboundary haze affecting Singapore and the region.
High likelihood of El Niño
2. According to MSS, there is high chance of an El Niño event occurring this year (more than 80 per cent chance). This assessment is supported by the presence of key precursors, including warmer sub-surface ocean temperatures in the eastern tropical Pacific. El Niño’s influence on Singapore’s climate is expected to be felt once the event becomes established.
3. El Niño events tend to have the greatest influence on Singapore’s rainfall during the Southwest Monsoon season from June to September, increasing the chance of dry conditions. During the last strong El Niño event in 2015/2016, Singapore’s total rainfall from June to September 2015 was about 35 per cent below the long-term average.
4. El Niño events also bring warmer temperatures to Singapore. Impact to temperatures is the highest during the period the El Niño event weakens, which is typically in March to May the year following the start of the event. During the decay of the last strong El Niño event in 2016, average temperatures in March – May were 29.2 degrees Celsius or 1.0 degree Celsius above the long-term average for that period (Singapore’s second warmest March – May on record). 2016 remains one of Singapore hottest years on record, tied with 2019 and 2024.
5. At this juncture, there is considerable uncertainty in the predicted strength of the El Niño. The strength of the El Niño event is more likely to be moderate when it starts, with the potential to become strong during the latter part of the Southwest Monsoon season (August to September).
Potential Positive Indian Ocean Dipole (IOD)
6. Besides El Niño, the IOD is another climate phenomenon that can influence the weather around the tropical Indian Ocean. Most numerical models from global climate centres predict that a positive IOD may develop in July to August 2026. Singapore and our surrounding regions tend to experience drier conditions as sea surface temperatures in the eastern Indian Ocean are cooler, resulting in less cloud formation. Singapore’s driest year on record occurred in 1997 when both El Niño and positive IOD events occurred.
Risk of Transboundary Haze
7. The Southwest Monsoon period between June and September is the usual dry season for the surrounding region. As drier and warmer conditions are conducive to the development of peatland and vegetation fires, the hotspot and smoke haze situation in the surrounding region could escalate from June 2026, particularly in fire-prone areas. If fires develop in close proximity and prevailing south-easterly to south-westerly winds blow smoke haze from the fires towards Singapore, there is a risk of transboundary haze affecting Singapore. With an expected El Niño and potential positive IOD, the dry season this year could be more intense and prolonged compared to recent years , and extend into October.
8. MSS will continue to closely monitor the development of El Niño and IOD as well as the regional weather and haze situation and provide updates when necessary. Updates on haze and the El Niño are available on the MSS website at https://www.weather.gov.sg/warning-haze-information/ and https://www.weather.gov.sg/climate-el-la/.
Haze Preparedness
9. The 28 government agencies under the Haze Task Force (HTF), chaired by the National Environment Agency (NEA), are ready to roll out their respective action plans should the air quality be impacted by transboundary haze. Members of the public should refer to the 1-hour PM2.5 concentration as an indicator of current air quality, and the 1-hour PM2.5 associated personal guide when planning outdoor or strenuous activities over the next few hours. The 1-hour PM2.5 concentration level can be volatile and fluctuate throughout the day based on weather conditions, particularly during periods of transboundary haze. For planning of next day activities, members of the public are advised to refer to the 24-hour PSI and accompanying health advisories. In addition, it is also advised that air purifiers at home be checked to ensure that they are in proper working condition. More details can be found in NEA’s advisories which are available on the NEA website, myENV app, and the haze microsite. When a haze episode is imminent, NEA will provide haze forecasts through the aforementioned sites. Follow NEA’s Facebook and X (@NEAsg) for the latest updates.
10. With warmer temperatures typically associated with El Niño conditions in Singapore, members of the public may also refer to the MSS heat stress webpage at https://www.weather.gov.sg/heat-stress and the myENV app for the latest information on heat stress conditions.
1El Niño is a naturally occurring climate pattern associated with changes in both the ocean and atmosphere in the equatorial Pacific Ocean, including an abnormal warming of the surface waters in the eastern equatorial Pacific. Typically lasting nine to 12 months and occurring every three to five years, it produces widespread and at times severe changes in the global climate.
2The Indian Ocean Dipole (IOD) is similar to the El Niño but occurs in the equatorial Indian Ocean and of shorter duration, typically ending by December-January. The IOD varies between three phases – positive, negative and neutral.
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