On August 18, temperatures from Quang Tri to Danang, eastern areas from Quang Ngai to Dak Lak and Khanh Hoa are forecast at 35-36 degrees Celsius, exceeding 36 in places, with humidity at 55-60 per cent.
Forecasters warned that actual outdoor temperatures could be 1-3 degrees higher than forecasts, or more over surfaces such as concrete and asphalt.
The combination of high temperatures and low humidity could increase fire risks, particularly as electricity demand rises, while prolonged exposure to the heat may cause dehydration.
Health experts advised people to limit outdoor activities between 10 am and 4 pm, avoid strenuous exercise in hot conditions and drink enough water. The elderly, children and people with underlying conditions were advised to take particular care.
On August 17, hot weather affected the northern midlands and plains as well as areas from Thanh Hoa to Danang, eastern parts from Quang Ngai to Dak Lak and Khanh Hoa.
Temperatures at 1 p.m. generally ranged from 35-37 degrees Celsius, exceeding 37 degrees in some locations. Con Cuong in Nghe An recorded 37.8 degrees, Danang 37.7 degrees, Hoi Xuan in Thanh Hoa 37.4 degrees and Ha Tinh 37.3 degrees.
Average temperatures nationwide in August are forecast to be 0.5-1 degree Celsius above the long-term average, with higher levels possible in some areas.
The south-central coast is expected to see more hot days than usual this month, with severe and locally extreme heat possible. Heat in northern Vietnam and from Thanh Hoa to Hue, meanwhile, is expected to be less frequent than the long-term average.
In July, northern Vietnam experienced a widespread heatwave from July 12-14, with highs of 36-38 degrees Celsius and above 39 degrees in some areas.
Thanh Hoa to Hue and the south-central coast experienced three heatwaves during July, with temperatures generally reaching 36-39 degrees Celsius and exceeding 40 degrees in some locations.