Many areas have recorded moderate to heavy rainfall, with some hit by torrential downpours, thunderstorms and strong winds, leading to a marked drop in temperatures in mid-May.

According to the National Centre for Hydro-Meteorological Forecasting, the cold air system continued moving southward on May 8 across the northeastern region, the north-central provinces and parts of the northwest. Northeasterly winds strengthened to force 2-3, reaching force 3-4 in coastal areas, causing temperatures to fall rapidly.

Temperatures across the plains ranged between 23 and 26 degrees Celsius, while mountainous areas recorded 21-23 degrees Celsius. In some high-altitude areas, temperatures fell below 21 degrees Celsius, bringing unusually chilly conditions for this time of year.

In Hanoi, moderate rain and scattered thunderstorms were recorded from the night of May 7 into the morning of May 8, with some areas experiencing heavy rain. Temperatures dropped to around 22-24 degrees Celsius. Residents were advised to watch for localised flooding in low-lying streets during peak hours.

Conditions at sea also worsened. In the northern Gulf of Tonkin, northeasterly winds reached force 4-5, with gusts up to force 6 and waves of 1-2 metres.

From the evening of May 8, the northeastern waters of the East Sea were forecast to experience winds of force 6, with gusts of force 7-8 and waves reaching 2-3 metres, causing rough seas and posing dangers to vessels operating offshore.

Forecasters said minimum temperatures in northern Vietnam on May 8 would range from 21 to 24 degrees Celsius, while average temperatures would remain around 24-26 degrees Celsius. Temperatures were forecast to edge up slightly on May 9, though cool conditions would persist, with temperatures ranging between 25 and 27 degrees Celsius.

The meteorological agency warned that northern Vietnam, Thanh Hoa and Nghe An provinces  could receive rainfall of 15-30mm, with some areas likely to record more than 80mm. Ha Tinh province  was also forecast to experience scattered thunderstorms, with rainfall exceeding 50mm in some locations.

Forecasters warned that thunderstorms during the seasonal transition period could trigger severe weather, including tornadoes, lightning, hail and strong winds. Mountainous provinces face risks of flash floods and landslides, while low-lying urban areas are likely to experience localised flooding.

The adverse weather was expected to affect agricultural production, damage crops and homes, and increase transport safety risks on both land and at sea.

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