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Weather Indices

Weather Indices

  Weather Indices

Thermal Index

Estimated Surface
Temperature (oC)

Thermal Index
(Soaring Conditions)

Please note that the observations may change from time to time, as well as from place to place, for reasons ranging from changes in the synoptic situation to short-term or local changes due to the complex coastal and mountainous terrain in Hong Kong. Users are advised to exercise utmost care in interpreting the information presented here and to monitor the weather conditions closely.

For general enquiries on the content of this page, please call Experimental Officer (Aviation Weather Forecast and Warning Services) at 2926 8335 during office hours on Monday to Friday (except public holidays).

(1) Thermal Index

Consider an air parcel. If it is warmer than its surrounding it will rise. The Thermal Index is based on the temperature difference between the air parcel and its surrounding. It is commonly used to give an indication of the soaring conditions at various heights.

The latest Thermal Indices up to 5 000 feet (1 524 metres) are shown on the left. The user can input a forecast temperature to suit his/her circumstances. For the latest temperature distribution over Hong Kong, please refer to Regional Weather in Hong Kong.

Please click here for the latest visibility reports over Hong Kong.

As a general guideline+:

Thermal Index Soaring Conditions
0 or Above
Below 0

For information on rain clouds in and around Hong Kong, please visit Weather Radar Image.

+ Handbook of Meteorological Forecasting for Soaring Flight. World Meteorological Organization Technical Note No.158. (WMO - No.495).

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