According to the National Center for Hydro-Meteorological Forecasting, temperatures surged across northern Vietnam, the provinces from Thanh Hoa to Hue and the south-central coastal region on the first day of the large-scale heatwave.

As of 1pm on May 23, temperatures generally ranged from 35 to 37 degrees Celsius, with some areas climbing above 37 degrees. Hanoi was among the hottest locations nationwide, with Son Tay recording 37.7 degrees and Lang Station reaching 37.6 degrees. Vinh Yen Station in Phu Tho also measured 37.3 degrees.

With relative humidity dropping to only 50-55% at 1pm, combined with the urban heat effect caused by concrete buildings and heat-absorbing roads, outdoor conditions in the capital and other major cities felt significantly hotter than official weather station readings.

Meteorologists forecast that from tomorrow, May 24, the heatwave will intensify further in both strength and coverage, officially entering its most severe phase.

Specifically, on May 24-25, northern Vietnam, the area from Thanh Hoa to Hue and the south-central coastal region will experience severe to extremely severe heat, with temperatures widely ranging from 36 to 38 degrees and some locations surpassing 39 degrees. Relative humidity is expected to fall to as low as 40-45%.

Particularly on May 25, the center of extreme heat is forecast to shift toward central Vietnam. Areas from Thanh Hoa to Da Nang and eastern Quang Ngai are expected to experience especially dangerous conditions, with temperatures ranging from 37 to 39 degrees and some places potentially exceeding 40 degrees Celsius.

During the same period, southeastern Vietnam will continue experiencing hot weather, with daytime highs between 35 and 36 degrees, and some areas above 36 degrees.

Weather authorities warned that the most dangerous period of the day will be between 11am and 4pm. Residents are advised to avoid prolonged outdoor activity and regularly replenish water and electrolytes.

“People should especially avoid sudden temperature changes between the outdoor heat and air-conditioned spaces to minimize the risk of heat shock, exhaustion or stroke,” meteorologists emphasized.

Four consecutive days of extreme heat

According to forecasters, this widespread heatwave across northern Vietnam and the southeastern region is likely to persist until around May 27 or 28. In central Vietnam, the heat is expected to continue through May 28 before gradually easing.

Meteorologists believe the heatwave will peak between May 24 and 27, with maximum temperatures in northern and central Vietnam ranging from 36 to 39 degrees Celsius. Some areas in northern Vietnam and the western mountainous regions from Thanh Hoa to Hue may even see temperatures above 39-40 degrees.

Authorities also warned that actual outdoor temperatures could be 2-4 degrees higher, especially in areas dominated by asphalt roads and concrete infrastructure. Prolonged heat combined with low humidity also increases the risk of fires and explosions while posing serious health threats to the elderly, children and outdoor workers.

From the evening of May 27 through May 30, scattered showers and thunderstorms are forecast to return to northern Vietnam, with some areas likely to see heavy rain before conditions gradually improve.

The region stretching from Thanh Hoa to Da Nang and the south-central coast is also expected to experience scattered rain and thunderstorms from the evening of May 28 to May 30.

In southern Vietnam, scattered showers and thunderstorms are forecast from the night of May 25 through May 27, mainly during late afternoons and evenings, while hot daytime conditions continue. From the evening of May 27 onward, rain and thunderstorms are expected to become more widespread, with localized heavy rainfall possible.

Meanwhile, the Central Highlands will continue to see isolated showers and thunderstorms alongside sunny daytime weather. Southern parts of the Central Highlands may experience scattered evening storms from May 25-26, with heavier rain expected from May 27 onward.

Meteorologists cautioned that after several days of extreme heat, thunderstorms may trigger dangerous weather phenomena including whirlwinds, lightning, hail and strong gusty winds.

Bao Anh