HONG KONG – The Hong Kong Observatory issued a “very hot weather warning”, the second this year, at 6:45 am on Friday.

“To prevent heat stroke, avoid prolonged activities outdoors,” the government said in a notification.

It asked people to drink plenty of water and avoid beverages containing caffeine or alcohol.

ALSO READ: Hong Kong Observatory logs hottest July day on record

The Home Affairs Department has opened temporary heat shelters for people to take refuge from the heat and the shelters will remain open when the very hot weather warning is in force.

The public should carry and drink plenty of water to prevent dehydration while engaging in outdoor activities.

Spokesman, Centre for Health Protection, HKSAR

“Under the influence of prolonged heat, members of the public should stay on the alert to prevent heat stroke or other discomforts related to very hot weather and pay due attention to health conditions,” the forecaster said in its warning.

The Centre for Health Protection of the Department of Health reminded people, particularly those undertaking outdoor activities, to take heed of necessary measures against heat stroke and sunburn in very hot weather.

"The public should carry and drink plenty of water to prevent dehydration while engaging in outdoor activities," said a CHP spokesman.

Those engaged in strenuous outdoor activities should avoid beverages containing caffeine, such as coffee and tea, as well as alcohol, as they speed up water loss through the urinary system, added the spokesman.

People have been advised to seek help immediately and medical advice as soon as possible if symptoms such as dizziness, headache, nausea, shortness of breath or confusion develop.

"Infants and children, the elderly, pregnant women, those with chronic illnesses such as heart disease or high blood pressure, outdoor/manual workers, and individuals who are overweight are more vulnerable to heat stroke. They should pay special attention," said the CHP spokesman.

Urging people to avoid prolonged exposure to sunlight, the HKO said light-colored and air-permeable clothing, wide-brimmed hats and ultraviolet-blocking sunglasses can reduce the chance of sunburn by solar UV radiation.

READ MORE: Hong Kong enhances heat warning service

As the “Heat Stress at Work Warning” is now in effect, the Labour Department reminded employers and employees to take appropriate measures during the effective period of the warning to prevent heat stroke while working in hot weather or hot environments.  

Warning that employees working outdoors or in non-air-conditioned indoor environments face high levels of heat stress and are at a relatively higher risk of heat stroke, the department said employers should assess the risk factors of heat stress for employees at work and take necessary preventive and control measures.