Hong Kong to revamp heat stress warning system by end of August

Hong Kong authorities aim to revamp the city's heat stress warning system by the end of this month. Secretary for Labour and Welfare Chris Sun announced on Tuesday that the government is reviewing the system's thresholds to better tailor them to the city's weather and the challenges of climate change.

The move follows criticism that the Heat Stress at Work Warning system remained at the lowest alert level during record breaking temperatures. On August 9, the Hong Kong Observatory recorded 36.9 degrees Celsius at its Tsim Sha Tsui headquarters, the highest reading since records began in 1884. Former Observatory chief Lam Chiu ying described the existing mechanism as decorative because it failed to trigger higher alerts during this period.

The current system uses a three tier colour coded warning based on the Hong Kong Heat Index, which considers air temperature, humidity, wind speed, and solar radiation. Amber warnings are triggered at a reading of 30, while red and black warnings require readings of 32 and 34, respectively. Neither red nor black warnings have been triggered since the system was introduced in 2023. While red or black alerts recommend work stoppages for those with heavy physical workloads, the index is not binding upon employers.

Secretary Sun stated that the Labour Department and the Observatory are working to define how the system will be triggered to ensure seamless operation. He expressed confidence that the review would incorporate past experience and society's concerns.