A heat wave caused by a hot low-pressure system from the west has hit parts of the northern and central regions, the Central Hydrological and Meteorological Forecast Center said.
On May 9 the mercury hit 39 degrees Celsius in Yen Bai, Phu Tho, Thanh Hoa and Ha Noi.
In the Central Highlands and south-central regions, temperatures peaked at 38 degrees. In the south, however, there has been a two- to three-degree drop in temperature.
The heat wave is forecast to continue until May 12 with the mercury hovering at 36- 38 degrees.