Hato was the third tropical cyclone affecting Hong Kong in 2017. The highest tropical cyclone warning, No.10 Hurricane Signal, was issued for the first time since Severe Typhoon Vicente hitting Hong Kong in July 2012. Hato intensified significantly as it traversed the northern part of the South China Sea, momentarily attaining super typhoon intensity over the sea areas south of Hong Kong and the first time a super typhoon necessitating the issuance of tropical cyclone warning signals No.8 or above since Hope in 1979.
Hato formed as a tropical depression over the western North Pacific about 740 km east-southeast of Gaoxiong on the night of 20 August. It moved generally westwards across the Luzon Strait and entered the northeastern part of the South China Sea on 22 August, intensifying into a typhoon and tracking west-northwest towards the coast of Guangdong. During its approach towards the Pearl River estuary on 23 August, Hato intensified further and became a super typhoon that morning over the sea areas south of Hong Kong, reaching its peak intensity with an estimated sustained wind of 185 km/h near its centre. After making landfall over the coast near Macao and Zhuhai shortly after noon time, Hato entered western Guangdong and gradually weakened. It moved across Guangxi the next day and degenerated into an area of low pressure over Yunnan at night.
Hato brought severe storm surge to the coast of Pearl River estuary. Record-high sea levels were recorded at many places. A maximum storm surge of 2.79 m and a maximum sea level of 6.14 m were recorded at Zhuhai station. The coastal areas in Zhuhai including some underground carparks were flooded by sea water. Electricity and water supply in the city became unstable. A number of vessels ran aground about 30 km southwest of Hong Kong and 39 crew members were rescued. Hato brought damaging winds and storm surge to Macao. Extensive areas of Macao suffered damage and were seriously flooded, resulting in at least ten deaths and more than 240 injuries. The direct economic loss exceeded 8.3 billion MOP. A maximum sea level of 5.58 metres was recorded in A-Ma station, a record high in Macao since records began in 1925. Electricity and water supplies were also affected. In Guangdong, Guangxi, Fujian, Guizhou and Yannan, there were at least 15 deaths and one missing during the passage of Hato. Around 740 000 people were affected and over 6 500 houses collapsed, with direct economic loss exceeding 27.2 billion RMB.
The Hong Kong Observatory issued the No.1 Standby Signal at 8:40 a.m. on 22 August when Hato was about 660 km east-southeast of the territory. Local winds were light to moderate northerlies during the day. Squally thunderstorms triggered by high temperatures affected many places in the territory during the afternoon. As Hato edged closer to the coast of Guangdong, the No.3 Strong Wind Signal was issued at 6:20 p.m. when Hato was about 410 km east-southeast of Hong Kong. Local winds strengthened gradually in the small hours of 23 August, becoming fresh to strong northerlies, reaching gale force on high ground. The Observatory issued the No.8 Northeast Gale or Storm Signal at 5:20 a.m. when Hato was about 160 km southeast of the territory. Local winds strengthened rapidly afterwards, with northeasterly gales in many places and reaching storm force offshore and on high ground. With Hato expected to make a direct hit over the Pearl River estuary, the No.9 Increasing Gale or Storm Signal was issued at 8:10 a.m. when Hato was about 100 km south-southeast of the Hong Kong Observatory. Local winds strengthened further that morning and the No.10 Hurricane Signal was issued at 9:10 a.m. when Hato was about 70 km south of the Hong Kong Observatory. Gale to storm force winds generally affected Hong Kong, with winds persistently reaching hurricane force over the southern part of the territory and on high ground. Hato came closest to Hong Kong around 10 a.m. that morning with its centre passing only about 60 km south-southwest of the Hong Kong Observatory. As Hato made landfall to the west of Hong Kong, local winds gradually veered from northeasterly to southeasterly and started to subside. The No.8 Southeast Gale or Storm Signal was then issued at 2:10 p.m. With Hato weakening and moving away, the No.3 Strong Wind Signal and No.1 Standby Signal were issued at 5:10 p.m. and 6:20