On the morning of 24 October, a well-marked low-pressure area sat over the east-central Bay of Bengal, and forecasters on both sides of the Bay were watching it closely. The India Meteorological Department (IMD) expects it to become a depression that day and a deep depression on 25 October, then reach cyclonic-storm strength by the morning of 26 October as it tracks west-northwest towards the Andhra Pradesh and Odisha coasts. It could approach Andhra Pradesh around 28 October.
The Bangladesh Meteorological Department (BMD) reads the situation similarly, on a slightly later clock: a cyclone could form around 27 or 28 October, its meteorologists say. They put the chance of the system moving towards Bangladesh as very low, though not zero.
The country may still feel it. Rain may increase across coastal Khulna, Barishal and Chattogram from 27 October and reach Khulna, Rajshahi and Rangpur from 29 October.
Thousands of kilometres to the east, the tropical Pacific is running far warmer than normal, and it is natural to ask whether the two are linked.
The honest answer is that El Niño matters a great deal for the world's weather, and in some ways for Bangladesh's seasons, but there is little reason to blame it for this storm.
Understanding why is the best way to read the headlines in the weeks ahead.
Where El Niño stands
This is no longer an El Niño in the making. The US National Oceanic and Atmospheric Administration (NOAA) declared El Niño conditions in June, and its 8 October outlook gave 83% odds that the October-December average will reach historic strength, exceeding every El Niño in its records, which begin in 1950.
The World Meteorological Organization (WMO) says the event is now well entrenched and intensifying fast, with a peak expected around December, and forecasters are near-certain it will last through February 2027.
NOAA stresses that a stronger El Niño makes its typical effects more likely, not certain.
Here are five of them, and what each means for Bangladesh.
1. It rearranges the world's rain
El Niño begins as unusually warm water across the central and eastern tropical Pacific, and the atmosphere responds: storm clouds shift eastward and rainfall belts move with them.
Coastal Peru and Ecuador can be drenched, Australia and Indonesia tend to dry out, and parts of East Africa get unusually heavy seasonal rain.
Bangladesh's response is weaker and harder to read. A 2023 study in Earth Systems and Environment, covering 1981 to 2021, found above-normal monsoon rainfall in seven of the eight El Niño summers, including the two wettest seasons in the 41-year record (1987 and 2015).
The statistical link was nonetheless weak (a correlation of +0.21, not statistically significant), and the authors stress that eight events is a small sample. The pattern also runs opposite to India's, where El Niño tends to weaken the monsoon.
Two caveats keep this from being a forecast. The study covers the June-September monsoon, not the post-monsoon weeks Bangladesh is in now, and WMO's October-December outlook leans towards drier-than-normal conditions across the Indian subcontinent.
Seasonal tilts like that say little about any single storm: the Bay of Bengal system could bring heavy rain to coastal districts whatever El Niño is doing.
2. It raises the risk of drought and fire in some places
Where El Niño suppresses rain, the harm builds slowly: parched soil, struggling crops, strained water supplies. Australia, Indonesia and parts of southern Africa are the classic cases, and in Indonesia El Niño-linked droughts have repeatedly fuelled peat fires and cross-border haze.
Bangladesh has its own version in irregular rain and seasonal dryness, especially in the north-west, where farming leans heavily on irrigation. The current system pulls the other way: BMD has warned that early rain from a cyclone could damage winter crops such as potatoes and onions, and poorly drained fields are especially vulnerable.
Both extremes belong in one preparedness plan, with better forecasts, efficient irrigation and farm advice tailored to each locality. El Niño alone cannot say whether a given district will face drought or flood.
3. It lifts global temperatures
El Niño releases heat from the tropical Pacific into the atmosphere, and global air temperatures typically follow the ocean with a lag of a few months, which is why the warming is often clearest in the year after an event develops.
With this one due to peak around December, both the UK Met Office and the WMO have pointed to 2027 as a probable new record year, because the El Niño boost lands on top of warming already driven by greenhouse gases.
El Niño does not cause that long-term warming; it temporarily adds to it.
For Bangladesh, higher temperatures and humidity mean more heat stress for outdoor workers, farmers and city residents, and more demand for electricity and water from infrastructure that is already strained.
Heat-health warnings, accessible drinking water and protection for people who work outdoors are the practical answer.
4. It changes tropical cyclone activity, but not the same way everywhere
El Niño's cyclone fingerprints differ by ocean. In the North Atlantic it generally suppresses hurricanes by increasing wind shear. In parts of the central and eastern Pacific it creates more favourable conditions for tropical cyclones.
The Bay of Bengal sits in a more complicated middle. A 2022 study in npj Climate and Atmospheric Science examined October-December cyclones and found that El Niño, along with a positive Indian Ocean Dipole, tends to go with fewer cyclones forming at low latitudes, between 5°N and 10°N-a band that produces about 40% of the Bay's storms.
North of 10°N, the study found little ENSO influence on cyclone formation. WMO expects a positive Indian Ocean Dipole to peak this month before fading.
That matters now. Skymet Weather placed the centre of this low near 16°N on 23 October, well north of the band where El Niño's imprint is clearest. Its strength and track will be set by local sea temperatures, wind shear and moisture over the Bay, which makes El Niño a poor explanation for this storm.
The lesson for Bangladesh is practical: follow official forecasts and warnings, heed BMD's advice that fishing boats and trawlers stay out of deep water in the northern Bay, and keep cyclone shelters and evacuation plans ready.
A seasonal climate signal cannot replace storm-specific information.
5. It rewires the circulation that steers weather
El Niño shifts the large-scale winds that organise weather. Over the Pacific it alters the jet streams, the fast-moving currents high in the atmosphere that help steer storms, which is why winter storm tracks and rainfall across North America can look different in El Niño years.
Closer to Bangladesh, the key change is a weaker Walker circulation, the east-west loop of air over the tropical Pacific.
The 2023 study links Bangladesh's wetter-leaning summers to that shift: the same weakening of monsoon winds that tends to dry out India appears to gather moisture over Bangladesh.
Even so, national averages hide a lot, and rainfall can differ sharply between districts when countrywide totals look normal.
That is why the Bay of Bengal system is a reminder to watch more than the Pacific. A storm forming over the Bay can change coastal rainfall, sea conditions and fishing within days.
For farmers, water managers and disaster-response agencies, the sensible approach is to combine seasonal outlooks with daily bulletins.
Neither El Niño nor a single low-pressure system gives the full picture.
What to watch in the coming days-
Timing. IMD expects cyclonic-storm strength by the morning of 26 October; BMD says 27 or 28 October.
Rain and crops. Coastal Khulna, Barishal and Chattogram from 27 October; Khulna, Rajshahi and Rangpur from 29 October. BMD warns of possible damage to winter crops.
The name. The next name on the regional list is Arnab, proposed by Bangladesh, followed by Murasu.
BMD says whichever system reaches cyclone strength first will take Arnab, and a separate low over the Arabian Sea is also being watched.
The bottom line: plan for the season, act on the forecast
El Niño helps scientists judge how the odds are shifting for heat, drought, heavy rain and cyclones. It cannot say what will happen to a particular district next week, and Bangladesh's weather is shaped by several interacting systems, including the South Asian monsoon and conditions over the Indian Ocean and the Bay of Bengal.
So the system now forming over the Bay should be treated as a developing hazard that needs close monitoring: not as proof that El Niño is producing a cyclone, and not as a sign that Bangladesh will be hit.
For a country exposed to coastal storms, river floods, erratic rainfall and extreme heat, that distinction is crucial.
Reliable forecasts, clear communication, careful farm planning and early action are what turn climate information into protection.
A warming Pacific can influence weather on the other side of the world.
What it means for Bangladesh will be decided by local conditions, and by how well the country prepares for them.