It was 40 degree Celsius at noon on May 16 in Hanoi, and elsewhere in Quang Ninh, Hoa Binh, Nghe An, Quang Binh, Quang Tri, and Hue city.
Hanoians and their neighbours in other northern provinces are suffering the first heatwave of the year, with temperatures soaring between 36 and 40 degrees Celsius during daytime.
The heat is particularly bad in urban areas, where there are many buildings and few trees, according to Le Thanh Hai, deputy director of the National Centre for Hydro-Meteological Forecasting.
This heatwave, which is expected to last more than three days, has been caused by the combined effects of hot low pressure and a south-westerly wind, he said.
The sudden rise in temperatures has led to an increase in hospitalisations of children and the elderly.
More than 4,000 children have received health checks at the Central Paediatrics Hospital in the past two days while the Paediatrics Department at Saint Paul 's Hospital is being visited by more than 400 children per day.
About 70 per cent of them are experiencing coughing and high fever.
According to the Hanoi Load Dispatch Centre of Electricity of Vietnam, electricity usage topped 44,500MWh on the day, almost 50 percent higher than recorded in the first days of May.
They said that this sudden increase would lead to power cuts in some parts of the city, but confirmed that improvements had been made to the network's capacity.
People were advised to save electricity and turn off unnecessary electrical equipment.
The heatwave has not been bad news for everyone though. Proprietors of fruit juice shops, swimming pools and food delivery services have seen demand rocket.
According to the National Centre for Hydro-Meteological Forecasting, it is predicted that northern provinces will suffer eight heatwaves this year, lasting five to seven days each. Most will take place between May and July.
Deputy Director Hai said temperatures this summer will match those from last year.-VNA
