Tamil Nadu may experience heavy rainfall and cyclones differently from the rest of India during the expected strong El Niño conditions in 2026.
El Niño is the unusual warming of surface waters in the Pacific Ocean near Peru and Ecuador, which affects global weather patterns.
Unlike much of India, Tamil Nadu may receive heavy northeast monsoon rainfall due to moist winds from the Bay of Bengal and warmer sea temperatures.
During the 2015 El Niño, Chennai recorded 1,522 mm of rainfall in four days (December 1–4), causing devastating floods.
The Indian Ocean Dipole (IOD) is another climate phenomenon involving differences in sea surface temperatures between the western and eastern equatorial Indian Ocean.
Satellite observations showed that sea temperatures in the southern Bay of Bengal were about 1°C above normal in September 2026, which may support intense rainfall and cyclonic systems.