Singapore’s weather patterns are under scrutiny as experts assess the potential impact of an emerging El Niño event, which could bring hotter and drier conditions to the city-state. The Met Service has confirmed that El Niño events—monitored using the Nino3.4 index in the central-eastern equatorial Pacific Ocean—typically result in reduced rainfall and elevated temperatures, particularly during the southwest monsoon season (June to September).
A positive Indian Ocean Dipole (IOD) event, which occurs concurrently in the equatorial Indian Ocean, may further intensify these effects. The IOD, like El Niño, influences cloud formation and rainfall, with cooler sea surface temperatures in the eastern Indian Ocean suppressing moisture. In 1997, when both El Niño and a positive IOD coincided, Singapore recorded its driest year on record.
How El Niño Affects Singapore’s Weather
During the last strong El Niño event in 2015/2016, Singapore’s rainfall from June to September 2015 dropped by approximately 35% below the long-term average. The following year, as the event weakened, temperatures surged, with average March-to-May readings reaching 29.2°C—1°C above the norm—making it the second-warmest such period on record.
El Niño’s influence on temperatures peaks during its decay phase, typically between March and May of the following year. The Met Service notes that while El Niño primarily affects rainfall during the southwest monsoon, its warming effects can persist into the subsequent year.
Uncertainties and Possible Scenarios
Predicting the exact intensity of an El Niño event remains challenging, according to Associate Professor Xianfeng Wang of the Asian School of the Environment at Nanyang Technological University. Climate models currently suggest the upcoming event could be stronger than the 2023/2024 El Niño, though uncertainties persist.
The interaction between El Niño and other weather phenomena, such as a potential positive IOD, could either worsen or mitigate conditions. For instance, a positive IOD may amplify heat and dryness, while the northeast monsoon later in the year could provide some relief.
What to Expect Next
Over the next few months, additional field observations will help refine climate model projections. Current predictions indicate a possible stronger El Niño than the previous cycle, but the exact strength and duration remain unclear. Authorities and residents should prepare for potential disruptions, including water shortages and heat advisories.
Frequently Asked Questions
What triggers an El Niño event?
An El Niño is declared when sea surface temperatures in the Nino3.4 region exceed 0.65°C above normal for an extended period.
How does El Niño affect Singapore’s rainfall?
El Niño increases the likelihood of drier conditions, particularly during the southwest monsoon (June to September), as seen in 2015 when rainfall dropped by about 35% below average.
Can other weather phenomena influence El Niño’s effects?
Yes. A positive Indian Ocean Dipole may amplify dryness and heat, while the northeast monsoon could later provide temporary relief.
How is your community preparing for potential heatwaves or water shortages this year?