Hoang Phuc Lam, deputy director of the National Centre for Hydro-Meteorological Forecasting, said El Niño had officially developed, with central Pacific sea surface temperatures rising 0.9 degrees Celsius above average in early June.
Forecast models show El Niño is expected to persist for the next three to six months, with a 63 per cent probability of reaching a very strong intensity between November 2026 and January 2027.
Hotter weather is expected across much of Vietnam, with heatwaves forecast to affect northern, north-central and south-central regions between July and September.
Average temperatures nationwide are forecast to remain 0.5-1.5 degrees Celsius above normal through the end of the year, increasing demand for electricity and raising risks for agriculture and forest fire prevention.
The East Sea is forecast to see 8-10 storms and tropical depressions this year, fewer than the long-term average despite the strong El Niño.
Of these, three to five could directly affect Vietnam's mainland.
Storms are forecast to affect northern Vietnam in July-September and central regions in October-November, with possible impacts extending to the south l
Lam cautioned that although fewer storms are expected, those that form during El Niño periods often behave unpredictably, with rapidly changing intensity and tracks.
Below-average rainfall is forecast through the end of the year, with fewer widespread heavy rain events and an earlier end to the rainy season in central and southern Vietnam.
Rainfall in northern Vietnam during September is forecast to be 5-20 per cent below average, although some northeastern areas could receive 25-50 per cent more rainfall than normal in August.
Meanwhile, rainfall in the Central Highlands and southern Vietnam is expected to decline significantly between October and December, with some areas recording totals 20-40 per cent below average in December.
Experts warned that a strong El Niño could increase the risk of drought and localised water shortages during the 2026-27 dry season, particularly in the south-central coast, Central Highlands and southern regions.
Higher temperatures could also heighten the risk of forest fires and place additional pressure on agricultural production and water resources.
