El Niño
In one line: El Niño is the warm phase of the El Niño Southern Oscillation (ENSO), when the central and eastern equatorial Pacific becomes unusually warm.
How it works
Normally trade winds push warm water west towards Asia. In El Niño these winds weaken, warm water spreads east and global circulation shifts. Scientists track it with sea surface temperatures in the Niño 3.4 region. In India, El Niño is associated with weaker monsoons.
Why it is in the news
Niño 3.4 was 2 to 2.8°C above normal in July to September 2026, and the event is forecast to be among the strongest on record. In such years, post-monsoon cyclones in the North Indian Ocean tend to form closer to the equator and track towards Andhra Pradesh and Tamil Nadu, as Arnab did.
Where to go next
- Rapid intensification
- Tropical cyclone
El Niño in the news
- Cyclone Arnab crosses Andhra coast; El Niño helps explain its path and strength 29 October 2026
The Pacific warming that shifts Indian Ocean storms
- Editorial: A 'normal' northeast monsoon in a strong El Niño year can still bring floods 26 October 2026
The Pacific warming behind this year's weather.
Previous-year questions on this
- 2022 · GS1 · 10 marks Discuss the meaning of colour-coded weather warnings for cyclone prone areas given by India Meteorological Department.
- 2015 · GS1 · 12.5 marks How far do you agree that the behaviour of the Indian monsoon has been changing due to humanising landscape? Discuss.
- 2014 · GS1 · 10 marks Most of the unusual climatic happenings are explained as an outcome of the El-Nino effect. Do you agree?
- 2014 · GS1 · 10 marks Tropical cyclones are largely confined to the South China Sea, the Bay of Bengal and the Gulf of Mexico. Why?
- 2017 · Prelims With reference to 'Indian Ocean Dipole (IOD)' sometimes mentioned in the news while forecasting Indian monsoon, which of the following statements is/are correct? 1. IOD phenomenon is characterised…