Nguyen Van Huong, Head of the Weather Forecasting Department at the National Center for Hydro-Meteorological Forecasting, reported that from 3/4, northwestern Vietnam began experiencing heat, with daily highs of 35 degrees Celsius or more. By 6/4, this heat had expanded across most of the North.

Central Vietnam also faced heat from 3/4, which rapidly intensified. By 4/4, it became severe, with daily high temperatures reaching 37 degrees Celsius or more. Meanwhile, the Central Highlands and Southern Vietnam recorded widespread heat from 5/4.

The heat in Northern Vietnam is forecast to continue until 12-13/4, then gradually decrease. Maximum temperatures will be 34-37 degrees Celsius, with some areas in the Northwest potentially reaching 39-40 degrees.

In Central Vietnam, the heatwave will last until 13-14/4, with common temperatures of 36-39 degrees Celsius, and some places exceeding 40 degrees. For Southern Vietnam and the Central Highlands, the heat could persist until late April and early May, with maximum temperatures of 34-37 degrees Celsius. There might be a few days of reduced heat, but it will intensify again afterward.

People commuting in the heat in Hanoi. Photo: Giang Huy

Explaining the cause, Huong said that the heat in Northern and Central Vietnam is primarily due to the influence of a western hot low-pressure circulation combined with the föhn wind effect. This makes the air dry and causes temperatures to rise rapidly during the day. Daily highs in these areas are commonly 36-39 degrees, with some places in Central Vietnam exceeding 40 degrees Celsius.

Meanwhile, the Central Highlands and Southern Vietnam are affected by a stable air mass. This limits cloud formation, resulting in clear skies and prolonged sunshine from morning to afternoon, leading to high temperatures.

Due to different causes, the intensity of the heat also varies across regions. The heat in Northwestern and Central Vietnam is dry and intense, while in Southern Vietnam, it is prolonged, but maximum temperatures only range from 35-37 degrees Celsius.

Compared to multi-year averages, Huong noted that the heat in Northwestern Vietnam and provinces from Nghe An to Da Nang appeared from 30-31/3, about one week earlier than the usual pattern, which typically falls in the second week of April.

In Northeastern Vietnam, where widespread heat usually arrives in late May according to multi-year averages, this year it began in early April, approximately 15-20 days earlier.

In Southeastern Vietnam, the first heatwave of the year occurred from 16-19/2, about 10 days earlier than the multi-year average (which is usually from 28/2 to 8/3).

According to the meteorological agency, in April 2026, the intensity of the heat is expected to be more severe compared to the same period in previous years, concentrated in Northwestern Vietnam, provinces from Thanh Hoa to Hue, and Southern Vietnam. Average temperatures in April for Northern Vietnam and Thanh Hoa - Hue are forecast to be 1,5-2,5 degrees higher than the multi-year average; other regions will be 0,5-1,5 degrees Celsius higher.

From around May, the heat tends to occur more frequently and intensify in Northern and Central Vietnam, lasting until about August 2026, before gradually decreasing from September.

"Overall, the heat in 2026 is likely to be more frequent and intense compared to the same period in 2025," Huong stated.

Gia Chinh