The normally crowded Hoàn Kiếm Lake walking street was almost empty during the record-breaking hottest day on May 6, when temperatures in Hà Nội reached 41 degrees Celsius. — VNA/VNS Photo Tuấn Đức

All parts of the country will experience a dangerous level of ultraviolet (UV) rays, the National Centre for Hydrometeorological Forecast (NCHMF) has warned.

UV index, which is used to measure the intensity of UV radiation, will peak around 8-10 in all major cities during the week from May 15 to May 18.

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.

People are advised to take extra precautions because unprotected skin and eyes will be damaged and can burn quickly.

These precautions are: wearing protective clothing, hats and sunglasses, as well as ensuring hydration for the body.

In their statement, the NCHMF also forecast that the upcoming heatwave in the Northern and Central regions will increase and last until the end of May.

Average temperatures in May are also predicted to rise by about 0.5 to 1 degrees Celsius compared to last year's figures.

In the Southern regions, the Southwestern winds are starting to the growing intensity from May, with rainfall increasing and less sunshine in the area.

On Tuesday, the Northern and Central regions will see some thunderstorms and showers, before experiencing hot weather from Wednesday onwards.

The Central Highlands regions and Southern regions will have showers on Tuesday evening, and a high chance of heavy rain showers and thunderstorms from Wednesday all the way through the next week.

Experts also advised people to be vigilant of fires due to the higher consumption of electricity, as well as possible forest fires.

Experts also warn of adverse health effects such as dehydration, fatigue, and even stroke for people being exposed to heat for a long period. — VNS