People walk around Hoan Kiem (Sword) Lake on Tuesday morning well protected from the biting cold.
A very strong cold front has caused the mercury to fall in northern provinces and Hanoi.
Nguyen Van Huong, head of the Weather Forecasting Department at the National Center for Meteorological and Hydrological Forecasting, said this was the first major cold wave in the north in winter 2020-21.
A group of people clad in several layers for warmth walk in the Hoan Kiem pedestrian zone, a popular tourist spot.
Motorbike drivers wear masks, hats, mufflers, and coats on Long Bien Bridge, where windchill is pronounced.