The National Centre for Hydro-Meteorological Forecasting said cold air had affected most of the northeastern region.
On September 11, the northeast monsoon is forecast to continue bringing showers and thunderstorms to northern Vietnam, with moderate to heavy rain in some places. The lowest temperatures in the north early on September 11 will generally range from 22 to 25 degrees Celsius, falling below 20 degrees Celsius in some mountainous areas.
In Hanoi, rain, showers and scattered thunderstorms are forecast on the morning of September 11, with locally heavy rain. By midday and the afternoon, the weather is expected to turn sunny, with highs of 30 to 31 degrees Celsius.
This is the first cold spell to affect Vietnam in the 2026-2027 winter season, arriving around three to five days earlier than the multi-year average.
Central Vietnam is forecast to face prolonged heavy rain (Photo: Nguyen Hai).
The meteorological agency said a low-pressure area was active over the East Sea. Over the next one to two days, it is highly likely to strengthen into a tropical depression over the central East Sea, with a probability of about 80 per cent.
It may then intensify further into a storm.
Under the influence of the tropical depression, central Vietnam, the Central Highlands and southern Vietnam are expected to face another prolonged spell of heavy rain.
On September 11, areas from southern Nghe An to Danang, eastern Quang Ngai and the northern Central Highlands are forecast to see moderate to heavy rain, with rainfall totals of 30-60mm and more than 100mm in some places.
The southern Central Highlands and southern Vietnam are forecast to have moderate to heavy rain and thunderstorms, with rainfall totals of 40-70mm and more than 120mm in some places.
On September 12, areas from Ha Tinh to Danang and eastern Quang Ngai are expected to continue seeing moderate to heavy rain, with rainfall totals of 40-80mm and more than 150mm in some places.
During the same period, the Central Highlands and southern Vietnam are forecast to have moderate to heavy rain and thunderstorms, with rainfall totals of 30-60mm and more than 100mm in some places.
Notably, on the night of September 12 and during September 13, areas from Quang Tri to Danang and eastern Quang Ngai are forecast to see heavy rain and scattered thunderstorms, with rainfall totals of 50-100mm and more than 200mm in some places.
Heavy rain in central Vietnam is also warned to be likely to persist and develop in a complex manner.
From September 14 to 17, under the influence of an intertropical convergence zone stretching across central Vietnam, provinces in the region are highly likely to continue experiencing widespread moderate to heavy rain.
The meteorological agency warned that prolonged heavy rain could trigger whirlwinds, lightning, flash floods and landslides in hilly and mountainous areas, as well as localised flooding in low-lying areas.
Residents are advised to monitor the latest forecasts and warnings regularly in order to respond proactively.
