Cold and Very Hot Weather Warnings

Hong Kong experiences both hot and cold seasons. The Observatory maintains a close watch on the local temperature changes. It issues warnings whenever Hong Kong is expected to be generally threatened by cold or very hot weather, to alert members of the public to the danger of low body temperature in cold weather or the risk of heat stroke and sunburn in very hot weather.

Once issued, the warnings are broadcast over radio and television. If necessary, the Observatory will hold press briefings, through which members of the public are reminded to take necessary precautions.

If cold or very hot weather persists while the corresponding weather warning is in force, the Observatory will repeat the special announcements to remind the public to take necessary actions.

These warnings also alert relevant government departments, such as the Home Affairs Department to consider the need to take actions, such as the opening of temporary shelters.

It is important that members of the public take note of these warnings and take steps to protect themselves and their family against cold or very hot weather. For an update on the status of weather warnings, the public may listen to radio and television broadcasts, call the Observatory's Dial-a-Weather service at 1878200, browse the Observatory's website (https://www.hko.gov.hk) or use the mobile app "MyObservatory".

Members of the public should pay attention to safety when using electrical appliances during cold and very hot weather. For details, please visit the Electricity Information Corner of Electrical & Mechanical Services Department.

Actions to be taken for Cold Weather Warning

1. People are advised to put on warm clothes and to avoid adverse health effects due to the cold weather. You must also ensure adequate indoor ventilation.
2. If you must go out, please avoid prolonged exposure to wintry winds.
3. If you know of elderly persons or persons with chronic medical conditions staying alone, please call or visit them occasionally to check if they need any assistance.
4. Make sure heaters are safe before use, and place them away from any combustibles. Do not light fires indoors as a means to keep warm.
5. Please ensure that there is plenty of fresh air in your room when you are using an old-type gas water heater.

Actions to be taken for Very Hot Weather Warning

1. The public should beware of heat stroke. Under the influence of extremely hot weather, or prolonged heat, members of the public should stay on the alert, drink more water, take all necessary protective measures against the heat to prevent discomforts caused by very hot weather, and pay due attention to physical conditions. If symptoms such as dizziness, headache, nausea, shortness of breath or confusion develop, take rest and seek help immediately, and seek medical advice as soon as possible.
2. Elderly persons, pregnant women, infants and children, those with chronic illnesses, such as heart disease or high blood pressure, as well as the obese are more vulnerable to heat stroke. Watch out for any symptoms of heat stroke. Under extremely hot weather, beware of health conditions, ensure adequate rest, maintain normal body temperature, and avoid overheating of the body.
3. When engaged in work under hot weather or high-temperature environments, please refer to the Guidance Notes on Prevention of Heat Stroke at Work of the Labour Department and take necessary precautions.
4. When engaged in outdoor activities, drink more water and avoid over exertion. If not feeling well, take a rest in the shade or cooler place as soon as possible. Perform outdoor activities in the morning or late afternoon as far as possible. Under extremely hot weather, vigorous physical activities should be avoided.
5. During indoor activities, replenish water timely. If there is no air-conditioning, then windows should be kept open as far as possible and fans be used to maintain adequate indoor ventilation. Public facilities with heat sheltering may also be used.
6. Avoid prolonged exposure under sunlight. Light-coloured and air-permeable clothing, wide-brimmed hats and ultraviolet (UV) blocking sunglasses can reduce the chance of sunburn by solar UV radiation.
7. Use a broad-spectrum sunscreen lotion of at least Sun Protection Factor (SPF) 15 (ideally higher) and reapply every two hours if you stay out in the sun, or after swimming, sweating, or towelling off.
8. Beware of health and wellbeing of elderly or persons with chronic medical conditions. If you know of them, call or visit them occasionally and check whether their household ventilation and air-conditioning devices function properly.
9. Those more vulnerable to heat stroke should avoid outdoor activities and stay away from hot environment as far as possible. Stay in cool, well-ventilated or air-conditioned places.

Hot Weather Special Advisory

Under such situations as high temperature, high humidity and light winds while the weather conditions remain below the level for issuing Very Hot Weather Warning, people may still be exposed to the risk of heat stroke if they do not take appropriate precautions. The Observatory will issue the "Hot Weather Special Advisory" through various channels when such weather conditions are expected. The advisory serves to remind the public as early as possible to avoid being affected by hot weather and take appropriate protective measures against the heat.

Educational Resources: Beware of Health Effects of Extremely Hot Weather