The National Center for Hydro-Meteorological Forecasting said the spell that gripped northern and central Vietnam on May 22-28 was the most intense for that part of the month since 2021, driving 11 weather stations to daily highs at or above their historical records.
Bac Ninh, northeast of Hanoi, reached 40.5 C on May 25, matching its May record, while stations in Hanoi and Nghe An climbed above 41 C.
What set the episode apart was its endurance. In many areas the sun bore down from around 9 a.m. until 7 p.m., and overnight lows held at 30-31 C, leaving an oppressive, sticky feel around the clock. The agency attributed the surge to a strong mass of hot, low-pressure air pushing in from the west, combined with a powerful foehn effect over central Vietnam that drove temperatures up across a wide area for days on end.
The heat is set to return almost immediately. Northern Vietnam faces a widespread heat wave on June 1-3, with highs of 35-36 C and above 37 C in places, while the band from Thanh Hoa to Da Nang and east toward Dak Lak swelters at 35-38 C through June 7. One to two more widespread heatwaves are likely later in the month, comparable to May's, peaking at 36-39 C and topping 40 C in the western mountains between Thanh Hoa and Hue. Average temperatures nationwide are forecast to run 0.5 to 1 C above the long-term norm for the month.
