According to the national weather agency, a low-pressure area in the west is expanding to the east and southeast, which, combined with foehn winds, will cause the temperatures in the northern, north-central and central-central regions to rise to 38C over the next two days.
The humidity will be relatively low at 35-50%, with temperatures of over 35C for a total of 11-17 hours a day.
The heat is expected to intensify from May 7-10, with temperatures averaging between 37C and 40C, and even higher in some locations.
The air will become drier during this period as humidity falls to 30-45% while there will be 10-18 hours total hours a day with temperatures of over 35C.
In the capital city of Hanoi, temperatures will rise to 35-37C from today to May 6 and up to 37-39C from May 7-10, before beginning to fall the following week.
