In the mountainous areas, including Mau Son district in Lang Son province, Sa Pa town in Lao Cai province, Pha Din Pass in Dien Bien province, and Tam Dao district in Vinh Phuc province, the temperature drops between three and five degrees Celsius.

The freezing weather conditions have caused heavy frost to cover high mountains such as Phia Oac in Cao Bang province, Lao Than in Lao Cai province, Fansipan in Sa Pa town, and Mau Son in Lang Son province.

According to the Lao Cai Hydro-Meteorological Station, the temperature on Fansipan is forecasted to drop to between one and three degrees Celsius on the night of December 22, with frost expected to continue.

This natural phenomenon is caused by the extreme cold spell that has spread throughout northern and north-central regions in recent days.

Some tourists are flocking to Sa Pa town in Lao Cai province to experience the cold and frost.

In particular, a cold spell combined with a strong northeast monsoon has caused temperatures in the northern region to sharply drop to two degrees Celsius, with frost occurring in mountainous areas such as Mu Cang Chai in Yen Bai province and Mau Son in Lang Son province.