The National Center for Hydro-meteorological Forecasting released a warning against medium to extremely high ultraviolet (UV) radiation levels in all three regions of Vietnam on Wednesday.
An UV Index reading of three to five is medium, six to seven is high, eight to 10 is very high, and above 10.5 means extremely high.
All of those UV index levels can cause harm to skin and eyes upon long unprotected sun exposure.
The northern localities will suffer moderate to very high UV index levels while provinces and cities in the central and southern regions will experience high to very high UV radiation benchmarks, according to the forecast.
The index was measured at 4.5 in northern Hai Phong City, 6.8 in northern Quang Ninh Province, 9.1 in Hanoi, 6.4 in central Thua Thien-Hue Province, 9 in central Quang Nam Province, and 8.1 in central Da Nang City from 11:00 am to 1:00 pm on Wednesday; and 6.6 in Ho Chi Minh City, 8.1 in Can Tho City, and 7.7 in southernmost Ca Mau Province between 10:00 am and 1:00 pm on the day.
It is forecasted that most provinces and cities across the country will see a very high UV index of eight to 10 from Thursday to Saturday.
The UV index in northern provinces and cities will decrease to the average level of two to four at the end of Saturday, while that in other regions will remain at a very high rate of eight to 10.
Experts advise people to wear hats, face masks, and sunglasses; cover bodies with thick fabric; and use sunscreen when traveling outdoors to prevent adverse impacts from sun exposure during those days.