A dry December
With less moisture in the lower atmosphere over the coast of southern China, December 2024 was much drier than usual in Hong Kong. Only traces of rainfall were recorded in the month, and it was one of 11 Decembers with just traces of rainfall since records began in 1884. The annual total rainfall of 2 309.7 millimetres was about 5 per cent below the annual normal of 2 431.2 millimetres. The monthly mean temperature was 18.5 degrees, 0.3 degrees above the December normal of 18.2 degrees.
The weather of Hong Kong was fine and dry on the first two days of the month. Under the influence of an easterly airstream and the subsequent northeast monsoon, apart from cloudy periods in the morning and at night, it was mainly fine during the day from December 3 to 7. With the strengthening of the monsoon and a band of clouds covering the coast of Guangdong, it became cloudier with cool mornings on December 8 and 9. The northeast monsoon moderated, and the weather turned warmer with sunny periods on December 10 and 11. The temperatures at the Observatory rose to a maximum of 25.2 degrees on the afternoon of December 11, the highest of the month.
Under the influence of a dry northeast monsoon, there were sunny periods with cool mornings from December 12 to 17. There were also a few light rain patches on the night of December 15. Affected by a replenishment of the winter monsoon, while it was cloudy in the morning, the weather turned fine and dry on the afternoon of December 18 and remained so for the next four days. The temperatures at the Observatory dropped to a minimum of 11.9 degrees on the morning of December 20, the lowest of the month. Under clear skies, the temperatures in the New Territories were significantly lower than those in urban areas on the mornings from December 19 to 21.
Under the influence of a broad band of clouds associated with tropical depression Pabuk over the southern part of the South China Sea, local weather turned mainly cloudy from December 23 to 27. There were also a few light rain patches on December 23, 25 and 26. Affected by a replenishment of the northeast monsoon, while it was cloudy at first, the weather turned fine and dry during the day on December 28 and remained so until the end of the month. With the onset of a fresh easterly airstream, the weather turned cloudy with a few light rain patches later on December 31.
One tropical cyclone occurred over the South China Sea and the western North Pacific in December 2024.
Details of issuance and cancellation of various warnings/signals during the month are summarised in Table 1. Monthly meteorological figures and departures from normal for December are tabulated in Table 2.
