Many people assume that El Niño automatically means drought and extreme heat in Bangladesh. While El Niño can certainly influence our weather, the relationship is much more complex than that.
One of the most important factors is what type of El Niño develops -- an Eastern Pacific El Niño (EPE) or a Central Pacific El Niño (CPE) (also known as El Niño Modoki).
Although both are El Niño events, they differ in where the warmest sea surface temperature (SST) anomalies are located across the tropical Pacific Ocean. This difference changes atmospheric circulation patterns, which in turn affect rainfall across many parts of the world, including Bangladesh.
For example, the 1997-98 El Niño was a classic EPE, with the warmest SST concentrated in the eastern Pacific Ocean. By contrast, the 2015-16 event more closely resembled a CPE, with the strongest warming occurring farther west.
This seemingly subtle shift had important consequences. It changed atmospheric circulation, displaced tropical convection toward the central Pacific, and altered monsoon patterns across Asia, leading to different regional climate impacts.
In general, an EPE tends to suppress the South Asian summer monsoon. As a result, Bangladesh often experiences below-normal rainfall, increasing the likelihood of prolonged dry spells, drought, and, in some years, more intense heatwaves.
A CPE, however, can produce a very different atmospheric response. Rather than consistently reducing rainfall, it may allow Bangladesh to receive near-normal or even above-normal rainfall. In some cases, it can even increase the risk of heavy rainfall and flooding, depending on how other climate systems evolve.
This is why simply saying, "An El Niño is coming, so Bangladesh will face drought," can be misleading.
Even then, El Niño is only one piece of the puzzle. Bangladesh's rainfall is influenced by several interacting climate drivers. Two of the most important are the Indian Ocean Dipole (IOD) and the Madden-Julian Oscillation (MJO).
These climate modes often interact with one another. Sometimes they reinforce El Niño's influence, while at other times they partially offset it. This is one of the main reasons seasonal rainfall forecasts remain challenging.
Current situation
As of now, the SST pattern associated with the developing 2026 El Niño resembles an EPE. However, the atmospheric response is, at least for the time being, displaying characteristics that are more typical of a CPE.
This mismatch between the ocean and atmosphere is not unusual during the early stages of an El Niño event, and it remains uncertain whether the atmosphere will eventually evolve toward a more classic EPE pattern or continue exhibiting CPE-like behavior.
For this reason, it is still too early to conclude whether Bangladesh will be significantly drier than normal in the latter part of 2026.
A reliable assessment requires monitoring not only the evolution of El Niño itself, but also the behaviour of the IOD, the MJO, and other large-scale climate drivers over the coming months.
Dr Rashed Chowdhury is a climate consultant and an Adjunct Professor at Arizona State University, USA. (Email: [email protected]).
