An unseasonably mild December
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With a band of clouds covering the coast of Guangdong, the weather of Hong Kong was mainly cloudy with one or two rain patches on the first four days of the month. Under the influence of a dry northeast monsoon, the weather turned generally fine and dry on December 5 and remained so on the following four days. With the return of a cloud band, it turned mainly cloudy with one or two rain patches on December 10 and the next morning. It turned generally fine during the day on December 11 as the clouds thinned out. With plenty of sunshine, the maximum temperature at the Observatory rose to 26.0 degrees that afternoon, the highest of the month. A fresh to strong easterly airstream affected the coast of Guangdong the next day. Locally, the weather remained mainly fine and dry.
A cold front moved across the coast of Guangdong on the late afternoon of December 13. Under the influence of its associated strong northeast monsoon, winds strengthened from the north and temperatures fell progressively. It was rather cool on the mornings of the next two days. Additionally, while one or two rain patches occurred on December 13 under the influence of a broad band of clouds, the weather turned generally fine on the night of December 14 under the influence of a dry northeast monsoon and remained so on the next three days. It was also very dry on December 14 and 15, with the relative humidity over most parts of the territory staying around 30 to 40 per cent during the day. With the return of a broad band of clouds, the weather became cloudier with one or two rain patches later on December 18 and the next day. As the cloud band thinned out, the weather turned generally fine and dry during the day on December 20.
Under the influence of a fresh to strong northeast monsoon, it was windier on the following two days. While it was fine and dry on December 21, the weather turned mainly cloudy on December 22 due to the approach of a cloud band and remained so on the following four days. While there were one or two rain patches on the morning of December 25, with a replenishment of the northeast monsoon reaching the coast of Guangdong that morning, the local weather became dry and cool that day. It remained dry with rather cool mornings on the following two days, with the temperature at the Observatory falling to a minimum of 13.8 degrees on the morning of December 27, the lowest of the month. Under the influence of the dry northeast monsoon, the local weather turned mainly fine from December 27 to 29. With the moderation of the northeast monsoon, winds subsided on December 30, with visibility falling below 5 000 metres over parts of the territory that morning. An easterly airstream brought cloudier weather on the last day of the month.
Three tropical cyclones occurred over the South China Sea and the western North Pacific in December 2025.
Details of issuance and cancellation of various warnings/signals in the month are summarised in Table 1. Monthly meteorological figures and departures from normal for December are tabulated in Table 2.
Ends/Monday, January 5, 2026
Issued at HKT 15:30
Issued at HKT 15:30
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