According to Hoang Phuc Lam, deputy director of the National Centre for Hydro-Meteorological Forecasting, abnormal warming in the equatorial Pacific could begin in June and persist through the end of the year, possibly extending into early 2027.
He said there was a 20-25 per cent chance the warming pattern could strengthen into a strong or very strong event, increasing the likelihood of more heatwave days than in 2025.
Average temperatures from June to December are forecast to be 0.5-1.5 degrees Celsius above normal, with severe heat expected to intensify across northern Vietnam and central coastal provinces between June and August.
Authorities said this year’s main weather threats would be extreme heat, drought and below-average rainfall. Nationwide, only 22-24 widespread heavy rain events are forecast, lower than historical averages.
Rainfall in northern and central Vietnam during September and October is forecast to be 5-20 per cent below average, while flows into major hydropower reservoirs on the Da River could drop by 10-30 per cent.
The weather agency also warned of higher risks of localised drought and water shortages in parts of central Vietnam and the Central Highlands, particularly from Danang to Khanh Hoa and in Gia Lai, Dak Lak and Lam Dong provinces.
Reduced upstream flows on the Mekong River later this year could also lead to earlier saltwater intrusion in the Mekong Delta during the 2026-2027 dry season.
Although storm activity in the East Sea is forecast to remain below average this year, officials warned that strong typhoons could still develop.
From June to August, around five tropical storms and depressions are forecast in the East Sea, with nearly two expected to directly affect Vietnam’s mainland.