Hong Kong considers lowering heat-stress warning thresholds amid criticism

Hong Kong officials are contemplating lowering the threshold for activating more serious heat-stress warnings during extreme heat events, following criticism that the system did not respond adequately when the city sweltered through its hottest day on record. The Labour Department's system currently factors in temperature, humidity, wind speed and solar radiation, but the weighting of these elements favors conditions that are more "muggy" than purely hot with strong solar radiation.

Commissioner for Labour Sam Hui Chark-shum explained that humidity and low wind speeds can significantly reduce cooling efficiency, leading to a higher health risk even at moderate temperatures. Despite adding eight new monitoring stations in April, the system did not issue a higher alert during the weekend despite temperatures exceeding 36.9 degrees Celsius, prompting the government to consider adjusting the activation thresholds.

Hui emphasized the need for a sensitive, scientifically sound approach that would address the underweighted factor of solar radiation in their original design, while also being cautious not to create a false sense of security by relying on localized indicators.