According to the National Center for Hydro-meteorological Forecasting, high temperatures of 36-40 degrees Celsius will be common in northern and central Vietnam from 10 a.m. to 5 p.m. over the next few days. Heat waves are expected to extend to May 19 in the northern and north-central regions and until May 20 in the central coastal provinces and south-central Vietnam. People have been asked to be alert and prevent any potential fires or wildfires in residential areas and to avoid outdoor activities from 11:00 am to 4:00 pm. People should also remember to drink enough water and follow a proper diet to enhance their immune system.