Around January 5, a new cold air mass is expected to intensify, bringing scattered rain and a significant drop in temperatures across northern and north-central Vietnam. Mountainous areas may experience severe cold and frost. Strong marine winds will stir up rough seas, with waves reaching heights of 4 to 6 meters.

According to the National Center for Hydro-Meteorological Forecasting, as of January 4, a cold air system is moving southward from the north. The northern region is currently seeing scattered light rain with temperatures ranging between 17°C and 20°C.

The forecast indicates that by tomorrow, January 5, this cold front will begin affecting northeastern parts of northern Vietnam, before spreading to the wider northern region, north-central provinces, northwestern areas, and even the central central region. Over land, northeast winds will blow at levels 2–3, and up to levels 3–4 near coastal areas. From the night of January 4 into January 5, northern Vietnam will see light and scattered rain.

As the cold air strengthens, both northern and north-central Vietnam will continue to experience low temperatures. Mountainous and midland areas in the north are expected to suffer from severe cold, with the potential for freezing temperatures. The lowest temperatures during this cold spell in northern Vietnam, Thanh Hoa, and Nghe An are forecast to range from 10°C to 13°C. In mountainous areas, the mercury may drop to between 7°C and 10°C, and even below 5°C in higher elevations.

In Hanoi, light rain and drizzle are expected from the night of January 4 to January 5. The weather will be cold, with temperatures dropping to between 10°C and 13°C.

At sea, from the evening of January 5, the Gulf of Tonkin will experience strong northeast winds at level 6, with gusts reaching levels 7–8. Waves will rise to 2–3 meters, creating rough sea conditions. In the northern part of the East Sea (including the Hoang Sa [Paracel] Islands), winds could strengthen to level 6 or 7, with gusts of level 8–9, and waves reaching 3–5 meters. The central and southern parts of the East Sea will also face increased northeast winds from January 6, with wave heights climbing to 4–6 meters.

Additionally, from tomorrow, provinces from Ha Tinh to Da Nang and the eastern parts of Quang Ngai to Gia Lai are expected to see showers, with some areas receiving moderate to heavy rain and thunderstorms. These storms may bring whirlwinds, lightning, hail, and strong gusts. In the mountainous regions of northern Vietnam, authorities advise caution against the formation of ice and frost.

Meteorologists have warned that the upcoming bout of cold weather, accompanied by hazardous conditions, may impact public health, particularly for the elderly, children, and those with chronic illnesses. Residents are advised to stay warm and avoid going outdoors early in the morning or late at night.

Extended periods of cold may also pose threats to agricultural activities, affecting livestock, poultry, and crops.

Localized heavy rainfall could result in flooding in low-lying areas, flash floods, and landslides in mountainous regions. Meanwhile, strong winds and high waves offshore pose significant risks to vessels and maritime operations.

Bao Anh