According to the World Health Organisation, a UV index of 7.5 to 10.4 is deemed "very high", which means a very high risk of harm from unprotected sun exposure.

A new heat wave is forecast to strike northern and central regions of Vietnam next week, with daytime temperatures to hit a high of 42℃, according to the National Centre for Hydro Meteorological Forecasting.

El Nino is set to return in late May or early June, with the weather pattern likely to last till early 2024, according to the National Centre for Hydro-Meteorological Forecasting of Vietnam.

Vietnam is forecast to experience extreme weather conditions and severe fluctuations in temperatures this summer.

The water level of Tri An hydropower reservoir, the largest of its kind in the southern region, has dropped to “dead level” due to a prolonged dry season and El Niño phenomena.

The East Sea has been forecasted to see a tropical depression in the next 24 hours, the first this year.

The first heat wave of this year’s summer, with temperatures peaking over 41 degrees Celsius, is predicted to scorch Hanoi as well as northern and central provinces until Sunday.

Regions across Vietnam are experiencing hot weather on May 4 with the temperature in some areas exceeding 37 degrees Celsius, according to the National Centre for Hydro-Meteorological Forecasting.

Ho Chi Minh City reached its highest levels of ultraviolet (UV) radiation with a scale of 9.8 on May 2 to become the hottest day of the year so far.