In an announcement sent to local schools on Monday, the Hanoi Department of Education and Training said that schools should also be flexible with class timings if the weather is cold, but temperatures remain above the threshold.

"Schools can decide to let students attend classes later than normal in the morning," the department said. "In cases where students show up late because of the cold weather, schools should allow them to attend classes without being penalised."

Schools have also been told to review school facilities and meals to ensure warm places and food and drinks for students.

The entire northern region has been forecasted to face continuous strong cold spells in the coming days.

According to the National Centre for Hydro-Meteorological Forecasting, a new cold front will affect the northern region from December 19 with average temperatures falling to between 9 -12 degrees Celsius in low-land areas and between 5-8 degrees Celsius in mountainous localities.