It is a quite strong cold snap that will cause temperatures in the north to drop sharply, according to Le Thanh Hai, deputy director of the National Hydro-meteorological Forecasting Centre.
Despite mild autumn climate, northerners have experienced warm weather over the past few days, with daily temperatures rising to 34-35 degrees Celsius.
However, temperatures will fall sharply when the cold snap strikes the northern region on the night of September 24.
Weather experts forecast temperatures will probably drop to 20 degrees Celsius at night and 22-25 degrees Celsius during daytime.
Meanwhile, typhoon Usagi was downgraded after pounding southern China on September 22, now packing winds of up to 88kmp near its centre.
The typhoon is forecast to change its course to west and south-west to head for northern border provinces of Vietnam in the coming 24 hours.
It will combine with the cold snap to bring heavy rains to Vietnam’s northern region in the coming days.
Mountainous localities are warned of flash floods and landslides.
