Dr. Hoang Phuc Lam, deputy director of the National Center for Hydro-Meteorological Forecasting, shared his assessment of the current heatwave and the outlook for Vietnam’s summer weather in 2026.

One of the harshest May heatwaves in recent years

Asked how the current heatwave differs from previous events during the same period, Lam said this is the second major heatwave of May 2026.

“The intensity and duration of this heatwave are more severe than the one recorded from May 13-16. It is also among the three most intense May heatwaves since 2021,” he said.

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Dr. Hoang Phuc Lam discusses the ongoing heatwave and Vietnam’s summer weather outlook for 2026. Photo: T.V.

According to official data, temperatures in northern Vietnam have surpassed those recorded during the early April heatwave, while central Vietnam has seen slightly lower readings.

However, the heat in the north is forecast to continue through May 27, while central provinces are expected to remain under extreme conditions until May 28.

With the heat expected to persist for another two to three days, temperatures in many areas could exceed 40C. Some locations may even reach 41-42C, comparable to the historic heatwave that struck central Vietnam in early April 2026.

El Nino beginning to form, hotter summer ahead

Responding to questions about the role of El Nino, Lam said the phenomenon is only beginning to develop and has not yet had a major impact on Vietnam’s weather and climate.

He explained that the current heatwave is mainly being driven by a western low-pressure hot zone combined with foehn winds generated by the Truong Son mountain range and the southwest monsoon.

However, from now through August 2026, El Nino is expected to push average temperatures nationwide roughly 0.5-1.5C above long-term averages.

That means this summer could be significantly hotter than usual, with more frequent and more intense heatwaves compared to both 2025 and historical averages. The likelihood of new all-time temperature records is also increasing.

In June alone, meteorologists forecast another two to three heatwaves with temperatures commonly ranging from 37-39C. Some areas could again reach 41-42C, especially mountainous western regions stretching from Thanh Hoa to Hue City.

At the same time, El Nino conditions could reduce the number of storms and tropical depressions in the East Sea, though unusual developments in storm intensity and trajectories remain possible.

El Nino is also commonly associated with widespread rainfall shortages of 25-50%, raising the risk of drought, water shortages and saltwater intrusion during the 2026-2027 dry season.

Historic drought and salinity intrusion events that affected southern Vietnam during 2015-2016 and 2019-2020 were cited as typical examples of El Nino’s impact.

Higher risk of thunderstorms and extreme weather after heatwaves

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Heatwaves are expected to intensify compared to historical averages. Photo illustration: Nam Khanh

Lam also warned that extreme weather events such as thunderstorms, strong winds and localized heavy rain are likely to increase following periods of intense heat.

During severe heatwaves, high temperatures combined with elevated humidity levels create stronger atmospheric convection, increasing the likelihood of afternoon and evening thunderstorms often referred to as “heat storms.”

At this time of year, despite the intense heat, the risk of hailstorms remains relatively low. However, the danger of thunderstorms, lightning strikes, localized flooding, flash floods and landslides is expected to remain high throughout May and June and could continue into July.

Areas facing the highest risk include northern Vietnam, particularly midland and mountainous regions, provinces from Thanh Hoa to Hue City, the Central Highlands and southern Vietnam, where seasonal transition conditions often trigger strong evening storms and localized downpours.

Lam urged residents to closely follow weather forecasts and severe weather warnings in order to take preventive measures and minimize damage caused by extreme weather events.

Bao Anh