The country's scientists have warned that global warming is exacerbating adverse weather, with the region sweltering under a heatwave in April - when neighboring countries also registered record temperatures.
A temperature of 44.1 degrees Celcius (111.38 degrees Fahrenheit) was measured in Vietnam Saturday, the National Centre for Hydro Meteorological Forecasting said, breaking the 2019 record of 43.4 degrees Celsius.
Farmer Nguyen Thi Lan told AFP that temperatures in the central city of Danang had been increasingly hot, forcing workers to start earlier than ever.
"We have had to finish before 10:00 am to avoid the heat," she said. Lan noted forecasters said temperatures had risen to nearly 40 degrees Celsius, "but at lunchtime, I think it was much hotter."
Vietnam's weather varies from north to south, but the entire country is now entering its hottest summer months. The record temperature was measured indoors at Hoi Xuan station in northern Thanh Hoa province. It topped the previous high of 43.4 degrees Celsius, recorded in April 2019 at Huong Khe District in central Ha Tinh Province.
"This is a worrying record in the context of climate change and global warming," climate change expert Nguyen Ngoc Huy told AFP from the capital Hanoi. "I believe this record will be repeated many times," he said. "It confirms that extreme climate models are being proven to be true."
Across the country, weather experts and authorities had warned the population to remain indoors during the hottest parts of the day.
Danang has asked Vietnam's industry and electricity ministries to "cooperate to effectively deal with the heat, possible drought, lack of water," according to state media. Officials have also told the city's water supply company to ensure that there are adequate "supplies of water for domestic use".
At midday Saturday, Hanoi city center was almost empty as many remained indoors to avoid the sun.
While both countries typically endure a hot period before the rainy season, the intensity of the heat has exceeded previous records.
Further west, the capital of Bangladesh -long dramatically impacted by climate change - recorded its highest temperature since the 1960s.
At the same time, Indian weather authorities said parts of the country were experiencing temperatures roughly three to four degrees above normal.
A recent report from the UN's Intergovernmental Panel on Climate Change warned that "every increment of global warming will intensify multiple and concurrent hazards".