The Hong Kong Observatory said it issued a Standby Signal No. 1 last December, which was the second time on record in Hong Kong since 1946 that it was necessary to issue a tropical cyclone warning signal in December.

With tropical cyclone Rai affecting the northern part of the South China Sea and skirting past to the south of Hong Kong, the Hong Kong Observatory issued the Standby Signal No. 1 on December 20.

It also became the storm which necessitated the issuance of a tropical cyclone warning signal so late in a year since 1946, the Hong Kong Observatory said.

Last December was warmer than usual with a mean temperature of 18.9 degrees Celsius, 0.7 degrees above the normal figure of 18.2 degrees Celsius.

It was also drier than usual with a total rainfall of 19.5mm, about 32% below the normal of 28.8mm.

The annual total rainfall of 2,307.1mm in 2021 was about 5% below the annual normal of 2,431.2mm.

Two tropical cyclones occurred over the South China Sea and the western North Pacific in the month, the Hong Kong Observatory added.