The coldest spell so far this winter will hit northern Vietnam later this week, according to the National Hydrometeorological Forecast Center.
Despite the onset of winter in November, the weather in Hanoi and northern provinces has been hot for the last 15 days due to the El Nino phenomenon.
But the center said a cold spell would hit the north Wednesday and intensify on Saturday, also bringing rain.
The maximum temperatures are forecast to drop to 18 degrees Celsius in the plains and 16 degrees Celsius in the mountainous areas.
Sa Pa in Lao Cai Province and Mau Son in Lang Son Province, two popular tourist spots, could see the temperature fall below 13 degrees Celsius.
The cold spell is expected to last until the end of the month.
Some central provinces will also be affected by the cold spell on Thursday, according to the center.