Hong Kong hoisted its highest “black” rainstorm warning at 5:50 a.m. on Tuesday, marking the fourth time in eight days the alert has been used—more frequent than in any previous year since the system was introduced almost three decades ago. The signal stayed in force for nearly 11 hours before being downgraded at about 5 p.m. The Hong Kong Observatory recorded more than 350 millimetres of rain by 2 p.m., the territory’s highest daily August total since records began in 1884. Hourly precipitation topped 100 millimetres in several districts, turning staircases into waterfalls and flooding riverside areas and major roads. The deluge shut all schools, law courts and register offices, while the Hospital Authority closed outpatient clinics and briefly diverted emergency patients from Queen Mary Hospital after its grounds were flooded. Government departments opened temporary shelters and suspended some services; the MTR sealed several station exits, and at least 103 flights were delayed or cancelled, according to airport data. The latest downpour follows deadly floods elsewhere in southern China and coincided with a red rainstorm alert in neighbouring Shenzhen. Meteorologists and former Observatory officials warned the cluster of extreme events is consistent with a trend toward more volatile weather linked to climate change, urging authorities to reinforce drainage and slope-stability measures.