On the sixth day of a cold wave in northern Vietnam, the average daytime temperatures were below 15 degrees in the plains, and below 13 degrees at higher altitudes.
Mau Son, situated at over 1,000 m above sea level, has been freezing with temperatures remaining below zero.
Some 23 out of 25 northern localities saw temperatures fall below 10 degrees on Friday, with 10 of them experiencing temperatures below 5 degrees, according to the National Center for Hydro-Meteorological Forecasting.
In some mountainous areas they were around 3 degrees, including in Sa Pa, Pha Din in Dien Bien Province and Dong Van in Ha Giang.
In Hanoi, for the first time this winter the Ba Vi weather station recorded 10 degrees. Lang, Ha Dong, Son Tay, and Hoai Duc recorded 11.
The actual temperatures outside the stations could be 2-3 degrees lower.
U.S. weather forecast service AccuWeather expects 9-18 degrees in Hanoi on Friday before the weather becomes steadily warmer and temperatures rise to 14-26 degrees by Dec. 28.
At higher altitudes like in Sa Pa, the minimum temperature will hover around 2 degrees for the next three days before rising gradually.
Meteorologists said the cold wave would persist in north for at least the next three days.
On Christmas's Eve temperatures are expected to be below 13 degrees.
On Friday Mount La Pan Tan in Yen Bai was covered in ice and frost. Local man Hoang Xuan Thanh, 30, said the ice began to form Thursday night when the temperature dropped to zero. It covered the ground, grasses and tree branches by 8 a.m. Friday.
"Most of the ice is at 1,700 m above sea level. The ice had not melted by 11 a.m."
Due to the impact of cold air, central localities like Thanh Hoa, Nghe An and Ha Tinh saw temperatures drop to 10-12 degrees.