In recent years, the frequency of abnormal heavy rains has been increasing. In the context of complex climate change, the rain trend is also more uncertain and unpredictable. Notably, the shift of ENSO phases in 2026 may create unpredictable weather patterns, especially the risk of localized heavy rain and extreme phenomena.
According to Mr. Nguyen Van Huong - Head of Weather Forecast Department, National Center for Hydro-Meteorological Forecasting, the forecast for the 2026 rainy season in regions across the country is generally approximately the average of many years.
The rainy season in the Central Highlands region is around the end of April 2026 - early May 2026, the South from mid-May 2026, the North around May 2026; in the Central region around September.
However, it is noteworthy that the rain distribution tends to be more extreme. The number of widespread heavy rains may be approximately or lower than the average, but localized heavy rains with very high intensity in a short period of time tend to increase" - Mr. Huong recommended.
According to the Head of the Weather Forecast Department, widespread heavy rains are likely to start from June 2026 in the North, then gradually spread to the South and end around November 2026 in the Central provinces. The risk of flash floods and landslides in the Northern and Central mountainous areas may increase, especially during the peak months of the rainy season and transitional periods.
Mr. Huong added that it should be noted that in the context of ENSO shifting phase to hot tilt and possibly moving towards El Nino at the end of the year, not only will the temperature increase, but thunderstorms, tornadoes, lightning, hail and localized heavy rain also tend to appear more and stronger than average. 2026 is therefore identified as a year of weather and natural disasters with higher extreme and unpredictable nature.
The period to pay special attention to is the seasonal transition months such as from March to May and September to October" - Mr. Huong said.
Regarding the oceanography trend, the Southeast coast is expected to have high tides. In November and December, the water level at Vung Tau station is forecast to exceed 4.3m, posing a risk of flooding in low-lying areas.
Regarding saltwater intrusion, in the early dry season of 2026, saltwater intrusion in the Mekong Delta is at a level close to the multi-year average and lower than the dry season of 2024 - 2025. From May to July, drought and localized water shortage outside the water supply area of irrigation works may occur in some areas of Gia Lai, Dak Lak and Lam Dong.
