In the Central Highlands, temperatures in places such as Dalat could fall to 10-12 degrees Celsius. Southeastern provinces may be colder than the Mekong Delta, with the chilliest spots in Xuan Loc and Ta Lai in Dong Nai and Phuoc Long and Dong Phu in Binh Phuoc, where temperatures could drop to 16-17 degrees Celsius.

In Ho Chi Minh City, temperatures could fall to about 17 degrees Celsius in outlying areas and around 18 degrees Celsius in the inner city, with lows around 3-4 am before warming up by midday.

“The cold spell will arrive later in the south and last longer, with temperatures rising again around January 27. In the north, temperatures are predicted to stabilise after January 24 and gradually rise,” Lan added.

She warned that unseasonal rain and cold, cloudy conditions could affect growers of apricot blossoms and other Tet flowers, as the plants need sunshine to store energy to bloom on time for the Lunar New Year or Tet.

During the cold spell, parts of the Mekong Delta such as Can Tho and Dong Thap could see minimum temperatures fall below 20 degrees Celsius, to around 19 degrees Celsius, before warming again.

Another reinforced cold air surge is forecast from January 29, affecting northern Vietnam and lasting until February 2-3. The southern region could see a similar cold spell from around January 31.

From now until the Kitchen Gods Day which falls on February 10, two cold surges are forecast to affect all three regions of Vietnam, she said. Each is likely to last three to five days, followed by a brief warm-up before the next surge arrives.