The likelihood of La Nina occurring in the coming months has decreased significantly compared to earlier forecasts. The strongest cold spells of the season are anticipated in late December, bringing widespread severe and extreme cold conditions.  

According to the National Center for Hydro-Meteorological Forecasting, seasonal weather forecasts from December 2024 to May 2025 have been released, outlining expected trends across Vietnam.  

Deputy Director Hoang Phuc Lam explained that ENSO (El Niño-Southern Oscillation) is currently characterized by sea surface temperature anomalies in the central equatorial Pacific that are 0.3°C below the long-term average (LTA) as of early November.  

The latest forecasts indicate a 50–55% chance of La Nina occurring in the next three months, but its intensity is unlikely to surpass the -0.5°C threshold needed to officially classify the phenomenon.  

Given this uncertainty, from December 2024 to February 2025, weather patterns, including storms, rain, and cold air, are expected to align with LTA conditions.  

Storms and rainfall patterns  

- Tropical storms and depressions in the East Sea are forecast to be near average (1.4 storms on average, with 0.2 affecting mainland Vietnam).  

- Most landfalling storms are expected to impact Central and Southern Vietnam.  

- Hazardous weather events like thunderstorms, lightning, and strong winds remain likely nationwide.  

- Heavy rainfall will persist in Central and South-Central Vietnam through late November and early December.  

Rainy seasons in the Central Highlands and Southern regions are expected to conclude later than usual—around late November for the Central Highlands and Southern Vietnam, and late December for the Central and South-Central regions.  

The coldest air masses are expected to intensify, especially in northern mountainous areas, during late December. These conditions may bring prolonged severe cold, frost, and icy conditions.  

Mr. Lam emphasized, “Severe and extreme cold spells in the Northern region are likely to occur on a widespread scale starting in late December, consistent with long-term averages.”  

Looking ahead to March–May 2025, ENSO is expected to shift to a neutral state, with a 55–70% probability.  

During this period:  

- Tropical storms in the East Sea are forecast to align with historical averages (0.5 storms, with none expected to make landfall).  

- Cold spells may still appear in March, though their intensity will diminish.  

- The Southern region may experience unseasonal rains during the dry season.  

Bao Anh