Hanoi (VNA) – The number of storms and tropical depressions forming over the East Sea and affecting Vietnam’s mainland in 2026 is forecast to be lower than the multi-year average, although unusual weather patterns and extreme events remain possible, according to the National Centre for Hydro-Meteorological Forecasting.
Providing an outlook for weather conditions from June to the end of 2026, Hoang Phuc Lam, Deputy Director of the centre, said the storm season is likely to begin around June, like previous years. However, total storm activity is expected to fall below normal levels.
On average, the East Sea records about 11–13 storms and tropical depressions each year, with 5–6 making landfall. This year, fewer than 11 systems are forecast to form, with fewer than five expected to directly impact the mainland.
Despite the lower frequency, Lam warned that storms may display unusual characteristics in both intensity and track, posing unpredictable risks. Short bursts of heavy rainfall could still trigger flash floods and landslides in mountainous areas, as well as urban flooding.
The ENSO cycle is projected to shift gradually into El Niño conditions between June and September 2026, with a probability of 85–95%, and persist into early 2027. Around 20–25% of El Niño events could reach strong intensity.
Under El Niño conditions, most regions across the country are expected to experience above-average temperatures, more frequent and intense heatwaves, and a higher likelihood of record-breaking temperatures. While storm activity may decrease, the systems that do develop could behave more erratically.
Rainfall across much of the country is forecast to decline by 25–50%, increasing the risk of localised or widespread drought, particularly in areas with high water demand for production and daily use during the 2026 dry season.
According to Lam, authorities have been urged to prepare for potential water shortages, drought, and saltwater intrusion in early 2027, similar to severe events recorded in 2015–2016 and 2019–2020 in the southern region.
Heatwaves are expected to be more frequent and intense than average, with the number of hot days in 2026 exceeding 2025 levels. In the Central Highlands and southern regions, heat is likely to ease from the second half of May. Meanwhile, northern and central regions will see peak heat from May to August, gradually subsiding from September and ending in October. Average temperatures nationwide are forecast to be 0.5–1.5 degrees Celsius higher than normal.
The rainy season is expected to begin in May in the north before shifting southward, ending around November in central provinces. Floods are likely on northern rivers from June to October, with water levels in upstream areas of the Red–Thai Binh river system reaching alert levels 2–3, while downstream sections may fluctuate around alert level 1.
River flows in northern regions are generally forecast to be below average. In central coastal areas, reduced river discharge could lead to localised water shortages, particularly in regions outside irrigation systems from Da Nang to Khanh Hoa and parts of the Central Highlands.
During the 2026 flood season, peak flood levels on rivers from Thanh Hoa to Ha Tinh and in Khanh Hoa are expected to range between alert levels 1 and 2, while rivers from Quang Tri to Dak Lak could reach levels 2–3, with some exceeding level 3. Flash floods and landslides remain a high risk in mountainous and upstream areas, and urban and riverside areas.
On the Mekong River, flood patterns are expected to remain close to average levels. However, upstream flows to the Mekong Delta in November and December may be lower than normal, raising the likelihood of earlier and more severe saltwater intrusion during the 2026–2027 dry season, Lam said./.
