Tourists visit Tsim Sha Tsui district under Super Typhoon Saola in Hong Kong, Sept 2, 2023. (EDMOND TANG / CHINA DAILY)

HONG KONG – Hong Kong experienced extreme weather in September with the city lashed by the second most intense typhoon in the South China Sea since 1950 and a “phenomenal" rainstorm that saw the highest hourly rainfall since records began in 1884, the Hong Kong Observatory said on Wednesday.

The Typhoon Signal No. 10 was raised for the first time since 2018 for Super Typhoon Saola on Sept 1 while the torrential rains on Sept 7 and 8 led to the issuance of the Black Rainstorm Warning that lasted for 16 hours and 35 minutes, the longest since the rainstorm warning system was introduced in 1992, the HKO said.

But despite the stormy weather, last month remained hotter than usual with a mean temperature of 28.5 degrees Celsius, 0.6 degrees above normal, while the city also saw 10 consecutive very hot days from Sept 21 to 30, the longest record of consecutive very hot days for September

“The Observatory recorded an all-time high September rainfall of 1,067.1 millimeters, more than three times of the September normal of 321.4 millimeters and easily breaking the previous record of 844.2 millimeters set way back in September 1952,” it added.

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But despite the stormy weather, the HKO said last month remained hotter than usual with a mean temperature of 28.5 degrees Celsius, 0.6 degrees above normal, while the city also saw 10 consecutive very hot days from Sept 21 to 30, the longest record of consecutive very hot days for September.

Flooding

Super Typhoon Saola struck on Sept 1 and 2, flooding some low-lying coastal areas of Hong Kong, including Sha Tin, Tai Po, and Tai O.

There were over 3,000 reports of fallen trees, 21 reports of flooding and two reports of landslides in the city. More than 80 people were injured while 460 flights were canceled at the Hong Kong International Airport.

On Sept 7, the weather again deteriorated in the city with heavy rain and squally thunderstorms due to a trough of low pressure associated with the remnants of Tropical Cyclone Haikui.

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During the torrential rain, the HKO registered a record-breaking hourly rainfall of 158.1 millimeters from 11 pm to midnight on Sept 7, the highest since records began in 1884.

“The two-hour total rainfall of 201.0 millimeters and 12-hour total rainfall of 605.8 millimeters recorded at the Observatory Headquarters during this phenomenal rainstorm also broke their respective records,” the HKO said.

“Moreover, the 24-hour rainfall from 4 pm on Sept 7 to 4pm next day reached 638.5 millimeters, about a quarter of the normal annual total rainfall of Hong Kong, and close to the highest records kept by the historical rainstorm on May 30, 1889,” it added.

The Observatory said more than 400 millimeters of rainfall were recorded over many parts of the territory and rainfall even exceeded 800 millimeters over the Eastern District and Southern District of Hong Kong Island on Sept 7 and 8.

READ MORE: Heavy rainfall floods 8 places in HK

Flash floods and landslides affected many parts of the territory, causing widespread traffic disruption and damage to infrastructure, the HKO said.

According to preliminary reports, there were 75 reports of landslides and 60 reports of flooding and at least two people were killed and more than 140 were injured during the rainstorm, it added.

Six tropical cyclones occurred over the South China Sea and the western North Pacific in September.