Hanoi temperatures reached 31 degrees Celsius at around 1 p.m. Wednesday, while areas over 1,500 meters above sea level like Sa Pa in Lao Cai reached 20 degrees, about 5-10 degrees higher than the previous weekends.

But the incoming monsoon starting Thursday is expected to befall northern mountainous regions and continue down below, bringing heavy rains, according to the National Center for Hydro-Meteorological Forecasting. Temperatures would be lowered, with Hanoi potentially reaching 18 degrees on Thursday and Friday, before rising slowly towards Sunday, up to 23 degrees, according to U.S. weather forecast service AccuWeather.

In Sa Pa, temperatures on Thursday could reach 12-20 degrees, with temperatures during the day hovering around 13 degrees during the weekends.

While rains and floods have receded in central Vietnam, the monsoon could bring the rain back to regions from Thanh Hoa to Quang Binh, Quang Tri and Thua Thien-Hue, starting Friday.

Central Vietnam should expect persistent rains for all of October. Meanwhile, the Central Highlands and southern Vietnam would see more rains at dusk towards the weekends.

Previously from Oct. 15 to 19, impacts of the now-dissipated Kompasu storm and cold air triggered heavy rains and floods in central Vietnam from Ha Tinh to Quang Ngai, killing at least three people and rendered three others missing.

As many as 54 communes in Quang Binh, Quang Tri, Thua Thien-Hue, Quang Ninh and Da Nang were flooded, and around 65 houses damaged. Thousands of hectares of paddy fields and other produces were also affected.

This year's winter is expected to be colder than previous years, and severe cold spells could appear even before Dec. 25, meteorologists warn.