The Vietnam Meteorological Agency has issued a nationwide seasonal hydrometeorological forecast bulletin (ie from December 2025 to May 2026).
According to Mr. Nguyen Duc Hoa - Deputy Head of the Climate Forecast Department, National Center for Hydro-Meteorological Forecasting, currently, the ocean atmospheric conditions are in a La Nina state with the standard deviation of sea surface temperature in the central Pacific (NINO3.4) at -0.7 degrees Celsius.
It is forecasted that in the next three months, the La Nina state is likely to continue to exist with a probability of 50 - 60%, while the probability of being neutral is from 40 - 50%.
"However, it is assessed that further, the La Nina phenomenon will remain short and have low intensity. It is likely that in the spring months of 2026, this La Nina phenomenon will gradually return to a neutral state with a probability of about 60 to 70%" - Mr. Hoa said.
In addition, according to Mr. Hoa, from March to May 2026, there is still a probability of ENSO in La Nina state of about 15 - 25% and a probability of El Nino state of about 15%.
With such impacts and weather patterns in the last months of the year, we predict that from now until the end of the year, there will be about 1-2 storms active in the East Sea area. Along with that, the development of rain is still likely to appear from now until the first half of December 2025. However, the level and intensity of rain will not be as strong as the rains in early November and October.
Regarding tropical cyclone activity, according to the Deputy Head of the Climate Forecast Department, from now until the end of 2025, there is a possibility of 1-2 storms or tropical depressions appearing in the East Sea.
"Storms and tropical depressions at the end of this season can still affect our mainland. The focus of the affected area at this time is mainly concentrated in the South Central region towards the South" - Mr. Hoa analyzed.
Mr. Hoa added that from January to May 2026, there is little chance of storms/tropical depressions appearing in the East Sea.
According to the average data of many years, from December of the previous year to February of the following year, there were about 1.4 storms or tropical depressions in the East Sea, 0.2 of which made landfall. From March to May, there are an average of 0.9 storms or tropical depressions in the East Sea every year.
Previously, in the past 3 months, from September to the first half of November 2025, there were 8 storms and 1 tropical depression in the East Sea. Of which, there are 5 storms affecting our mainland including storm No. 9 Ragasa, storm No. 10 Bualoi, storm No. 11 Matmo, storm No. 12 Fengshen and storm No. 13 Kalmaegi.
Since the beginning of 2025, there have been 19 storms and tropical depressions in the East Sea (including 14 storms).
Some concepts of ENSO according to the Institute of Meteorology, Hydrology and Climate Change:
El Nino: El Nino is a concept used to refer to the phenomenon of abnormal warming of the surface water layer in the eastern equatorial Pacific Ocean. El Nino is also known as the "hot spot".
La Nina: In contrast to El Nino, La Nina is a concept used to refer to the abnormal cold phenomenon of the surface water layer in the eastern equatorial sea of the Pacific Ocean. La Nina is also known as the "cold flood".
Southern fluctuations (SO): SO is a concept used to refer to the fluctuation phenomenon of the pressure difference between the western and central equatorial Pacific.
ENSO: Because the two phenomena El Nino/La Nina (ocreatic) and SO ( atmospheric) occurring on the equator TBD are closely related, they are linked together into a dual phenomenon, abbreviated as ENSO.
