Less than a fifth of young people know about the dangers of too much direct sunlight. Fewer than 20 per cent of 3,000 students surveyed knew ultra-violet (UV) rays in sunlight posed a danger to their health.
UV rays can cause early skin ageing and blindness.
The pupils in the survey were aged 11 and 12.
The group which did the survey said the public needed to be told. They said the effects of UV rays add up over years. Young people need to be warned of the risks more often.
People can protect themselves with sun screen and umbrellas. In Hong Kong, high UV index levels were measured. There were 20 high UV days a month between May and September.