The probability of El Nino reaching very strong intensity late this year has risen to 98 per cent, five percentage points higher than forecast a month earlier, meteorological experts said.
According to Nguyen Duc Hoa, deputy head of the Climate Forecasting Division, the phenomenon is expected to remain very strong from January to March 2027, although the probability will be lower than in October-December, and could persist into early summer.
Hoa added that number of tropical depressions and storms in the East Sea between October and December, as well as those affecting Vietnam, was likely to be below the long-term average.
The East Sea typically records 4.5 tropical depressions and storms during the period, with 1.9 making landfall.
Meteorological and climate change expert Nguyen Ngoc Huy said a very strong El Nino could result in fewer floods and storms than in 2025, but warned that very powerful storms could still occur.
Average temperatures nationwide are forecast to be 1-2 degrees Celsius above the long-term average in October and November, with some areas even warmer.
In December, temperatures are expected to be 0.5-1.5 degrees above average in most areas and 1.5-2.5 degrees higher in the Central Highlands and southern Vietnam.
Moderate to heavy rain is forecast nationwide in October, easing in November, while the rainy season could end early in the Central Highlands and southern Vietnam.
Cold air is also expected to be weaker than average, with severe cold spells likely to arrive later and occur on fewer days.
Higher temperatures, earlier heat in southern Vietnam
From January to March 2027, temperatures are forecast to remain above average nationwide, by 0.5-1.5 degrees Celsius in most areas in January and generally 1-2 degrees in February and March.
Hot weather could arrive earlier than usual in southern Vietnam from February, while localised heat could develop in the northwest from March.
Tropical depressions and storms are unlikely to develop over the East Sea between January and March. The long-term average for the period is 0.6 systems, with none making landfall.
Northern Vietnam is also expected to have fewer days of drizzle and light rain from late February.
January-March rainfall is forecast near average in northern Vietnam but lower elsewhere, with the upper Mekong basin expected to receive 15-30 per cent less than normal.
Experts urged local authorities and residents to closely follow official weather warnings, particularly forecasts for heavy rain, flooding and landslides, and to prepare for early evacuation in vulnerable areas when necessary.
They also recommended that the Central Highlands and Mekong Delta begin storing water in reservoirs and canals early to prepare for possible shortages during the 2027 dry season.
