The 2025 national climate change scenario, released by the Ministry of Agriculture and Environment, projects that both cities will continue to warm throughout the 21st century, and that their urban cores will heat up more quickly than the citywide average.

Under the high‑emissions pathway, average annual temperatures could rise 1.7‑2 °C by mid‑century and 3‑3.4 °C by the end of the century in Hanoi, with similar increases expected in Ho Chi Minh City, according to Nguyen Huu Quyen of the Institute of Meteorology, Hydrology, Environment and Marine Sciences.

In inner Hanoi, days with maximum temperatures above 35 °C may increase by 30‑70 by mid‑century and by 50‑90 by 2100. In inner Ho Chi Minh City, the same metric could rise by 35‑70 by mid‑century and by 90‑100 by the end of the century, Quyen said.

The faster warming of city centres is linked to the urban heat‑island effect. Dense concrete, asphalt and scarce green space absorb and store heat, making downtown areas hotter than surrounding suburbs.

Deputy director Truong Ba Kien, of the institute’s meteorological research centre, warned that Vietnam would no longer have a winter from around the middle to the end of this century.