Hong Kong endured its heaviest August downpour since records began in 1884, prompting the city’s fourth ‘black’ rainstorm warning in eight days—an unprecedented frequency since the alert system was introduced in 1998. The Hong Kong Observatory measured 355.7 millimetres of rain by 2 p.m. on Tuesday, with hourly totals topping 100 mm in some districts. The warning, first hoisted before dawn, remained in force for more than 11 hours before being downgraded late in the afternoon. The deluge flooded streets and low-lying areas, forcing the shutdown of school classes, court hearings and outpatient services at several hospitals, including flood-hit Queen Mary Hospital. Airport data showed 103 flight delays or cancellations, while rail operator MTR sealed multiple station exits and government offices curtailed services. Drainage authorities reported at least 25 flooding incidents, and the weather bureau kept a landslip alert in place as torrents turned hillside stairways into waterfalls. The latest storm struck as mainland authorities grapple with earlier flooding. Beijing, which apologised for being under-prepared after deadly rains last week, evacuated more than 82,000 people and issued a top-tier red rain alert on Monday. Farther south, Shenzhen raised its first city-wide red rainstorm warning since 2018 amid overnight downpours, and neighbouring Guangdong kept flood-control measures on high alert. Extreme conditions extended beyond China. Japan logged a national record temperature of 41.8 °C in the central city of Isesaki on Tuesday, surpassing a week-old high and prompting government heat-stroke advisories and pledges to protect rice crops. Meteorologists say a stalled East Asian monsoon and longer-term climate change are fuelling the concurrent bouts of torrential rain and searing heat across the region.