Hong Kong considers lowering heat-stress warning thresholds amid criticism

Hong Kong authorities are mulling a reduction in the temperature and solar radiation thresholds for initiating more severe heat stress warnings, following backlash over the system's performance during the city's hottest day on record. Current warnings are more attuned to "muggy weather" than strictly high temperatures and strong solar radiation, according to Labour Commissioner Sam Hui Chark-shum.

The system considers factors like air temperature, humidity, wind speed and solar radiation, but their importance is "localized" for Hong Kong's climate. Hui explained that high humidity and slow wind speed can significantly reduce cooling efficiency, potentially posing greater health risks than higher temperatures in well-ventilated spaces.

The department came under fire after its warning system remained at the lowest level during the city's 36.9°C peak on Sunday, even though temperatures in certain areas surpassed 39°C. The Labour Department is considering lowering the activation thresholds for extreme heat, with the review expected to conclude by the end of the summer.

Critics argue that localized heat stress alerts could create a false sense of security, overlooking risks in certain working environments. Former politician Emily Lau Wai-hing also urged the Correctional Services Department to review heat prevention policies in prisons, highlighting the high risk of heatstroke in enclosed environments.