The northern region and central coastal provinces are forecast to sizzle as temperatures hit a scorching 40 degrees Celsius, or 104 degrees Fahrenheit, in the early days of July.
Residents in the northern and central regions were braving temperatures of over 37 degrees Celsius on Sunday, 0.5 to 1.5 degrees against a day earlier.
Temperatures of over 39 degrees Celsius were experienced in Hanoi and nearby provinces of Hoa Binh, Vinh Phuc, Hung Yen, Ha Nam, Ninh Binh, and some parts of the central region like Thanh Hoa, Nghe An and Thua Thien-Hue, according to the National Center for Hydro-Meteorological Forecasting.
RealFeel temperatures, which indicate how hot it feels outdoors, ranged from 42 to 45 degrees Celsius in the areas.
Hoang Phuc Lam, head of Climate Forecasting Department at the center, said that people, especially children and the elderly, should drink enough water and avoid outdoor activities.
State monopoly Vietnam Electricity (EVN) raised concerns over a looming power shortage as a result of the heat wave. It warned companies and households to minimize electricity consumption, especially during peak hours, to avoid overloading the grid, which would lead to power cuts.
Nationwide power consumption was measured at a record-breaking 711 million kilowatt-hours (kWh) on June 22, up 11 percent against the peak day of last year, EVN said.
The northern and central coast regions have been baking in hot weather for several days, and the heat is set to become more intense from now until Wednesday.
Weather forecasters say temperatures will start to drop from Friday onwards.