Southern Vietnam nears end of rainy season

The Southern Regional Hydro-Meteorological Station said the southwest monsoon has now ended across the southern region.

Northern, northwestern, and northeastern winds have become dominant. 

These wind patterns are typical of the dry season, when descending air currents suppress cloud formation and lead to very little rainfall.

The rainy season in southern Vietnam usually begins in the second half of May and ends around November 10-20 each year.

However, meteorologists said 2025 has been an irregular year.

In several localities, the rainy season arrived earlier than the long-term average. 

Even within the same province, the start of the rainy season varied widely, with some places seeing delays or early onsets differing by nearly a month.

This year’s rainy season is also ending later than usual.

Several southern provinces are expected to officially transition into the dry season only in the first week of December, later than the annual norm.

As the region moves into the dry season, southern Vietnam is also experiencing a pronounced cold spell driven by a strong surge of cold air pushing deep from the north.

Although daytime conditions still include light sunshine, temperatures in Ho Chi Minh City and many southern localities have dropped sharply compared with previous days, signaling a clear seasonal shift.

Le Dinh Quyet, head of the forecast department at the Southern Regional Hydro-Meteorological Station, told Lao Dong (Labor) newspaper that cumulative rainfall across most southern provinces and Ho Chi Minh City has exceeded multi-year averages.

This is due to multiple episodes of heavy rain throughout the year, with some localities recording single-day totals of more than 100mm.

Regarding the current cool weather, the southern region’s weather agency said the cold spell is being fueled by a strong reinforcement of cold air moving southward.

Daytime temperatures have fallen by about 1-2 degrees Celsius compared with recent days and are expected to continue dropping gradually as the cold air mass spreads.

Temperatures in Ho Chi Minh City may reach 19-20 degrees Celsius for several consecutive days.

Meteorologist Le Thi Xuan Lan told Thanh Nien (Youth) newspaper that the unusually early and deep cold this year is partly linked to La Niña conditions.

However, she said La Niña is relatively weak and only one contributing factor.

La Niña events are associated with strong and persistent monsoon winds, abundant rainfall, and more frequent storms and tropical depressions.

A significant part of the anomaly, she added, comes from intensifying climate change, which is making weather increasingly extreme and unpredictable.

Lan noted that it is still only the final days of November, while the core winter period in Vietnam typically begins in December and can last through January or even into February.

With the current trend, both the frequency and intensity of cold spells are likely to increase in the coming months.

A stronger cold surge is forecast to affect northern Vietnam on December 3-4 before spreading southward around December 6-7.

This next wave could push temperatures in Ho Chi Minh City and neighboring provinces below 18 degrees Celsius, Lan said.

According to the National Center for Hydro-Meteorological Forecasting, La Niña conditions are likely to persist for the next three months.

During the rest of 2025, Vietnam may still experience one to two tropical storms or depressions, mainly affecting the south-central coastal region and areas farther south.

From December through February 2026, northern Vietnam could face widespread and severe cold, particularly from the second half of December, with risks of frost and icy conditions.

The national weather agency also warned of unseasonal rainfall in the Central Highlands and southern Vietnam during the first months of the dry season.

These rains could be accompanied by thunderstorms, strong gusts, lightning, and even hail.