November 2024 was characterised by the successive strikes of tropical cyclones Yinxing, Toraji and Man-yi at the end of the typhoon season of Hong Kong, necessitating the issuance of tropical cyclone warning signals for these three episodes, the first time in November since 1946. With stronger than normal cyclonic flow in the lower atmosphere over the coast of southern China, the month was also cloudier and wetter than usual. The mean amount of cloud in the month was 71 percent, 13 percent above the normal of 58 percent. The monthly total rainfall recorded at the Hong Kong Observatory was 194.1 millimetres, about five times of the November normal of 39.3 millimetres and the second highest on record for November, just after 224.2 mm recorded in November 1914. The accumulated rainfall up to November this year was 2309.7 millimetres, a deficit of around 4 percent compared with the normal of 2402.4 millimetres for the same period. Despite the rather gloomy and rainy conditions, the month was warmer than usual with the mean temperature of 23.0 degrees, 0.8 degrees above the normal and one of the ninth highest on record for November. Together with the higher than usual temperatures in September and October, the autumn of this year from September to November was much warmer than usual. The mean temperature of 26.5 degrees and mean minimum temperature of 24.5 degrees were both the highest on record for the same period. Moreover, the mean maximum temperature of 29.2 degrees was one of the highest on record for the same period.

Under the influence of a dry northeast monsoon, the weather of Hong Kong was fine and dry on the first day of the month. With plenty of sunshine, temperatures at the Observatory rose to a maximum of 30.6 degrees that afternoon, the highest of the month. With a band of clouds covering the coastal areas of Guangdong, local weather turned cloudier in the following few days with a few light rain patches on 3 – 4 November. While there were still a few rain patches at first on 5 November, the weather turned dry with sunny periods during the day with the arrival of a replenishment of the northeast monsoon. Under the prevalence of the dry northeast monsoon, it was generally fine during the day on 6 – 7 November apart from a few light rain patches in the morning.

Meanwhile, an area of low pressure over the western North Pacific to the east of the Philippines intensified into a tropical depression on 3 November and was later named Yinxing. It moved northwestwards towards the northern part of Luzon and progressively intensified into a super typhoon in the following four days. After skirting past the northern part of Luzon, Yinxing tracked generally westwards across the northern part of the South China Sea on 8 – 9 November. It then turned to move southwestwards over the seas southeast of Hainan Island and weakened gradually on 10 – 11 November. Yinxing finally weakened into an area of low pressure over the coastal waters of central Vietnam on 12 November.

Besides, another area of low pressure over the seas east of the Philippines progressively intensified into a tropical storm and was named Toraji on 9 November. It then moved west-northwestwards towards Luzon and progressively intensified into a typhoon in the following two days. After moving across Luzon, Toraji entered the central part of the South China Sea on the afternoon of 11 November. It then tracked generally northwestwards towards the coast of Guangdong on 12 – 13 November and weakened gradually. Toraji turned to track slowly westwards across the seas south of Hong Kong on the morning of 14 November. It finally weakened into an area of low pressure over the seas south of Shangchuan Dao on the morning of 15 November.

Furthermore, an area of low pressure over the western North Pacific progressively intensified into a tropical storm and was named Man-yi on 9 November. It moved towards Luzon in the following seven days and intensified into a super typhoon on 16 November. After moving across Luzon on 17 November, Man-yi tracked generally west-northwestwards across the northern part of the South China Sea the next day and weakened. Man-yi gradually turned to track southwestwards on the afternoon of 19 November and finally weakened into an area of low pressure over the seas southeast of Hainan Island on the morning of 20 November.

While the weather of Hong Kong was fine and dry during the day on 8 November, with the approach of Yinxing, it turned cloudy with isolated showers at night. Under the combined effect of the northeast monsoon and Yinxing, the weather of Hong Kong was mainly cloudy with a few showers on 9 – 10 November. Strong winds affected many places of the territory on the night of 9 November and the next morning. With Yinxing departing from Hong Kong, local winds moderated gradually during the day on 10 November.

While there were a few isolated showers at first on 11 November, the weather turned mainly fine on the afternoon and the next day. With the approach of Toraji, the weather of Hong Kong deteriorated again with a few squally showers on 13 November. Local winds also strengthened gradually in the afternoon. As Toraji was expected to come rather close to Hong Kong with its associated gale force winds posing a threat to the territory, the Observatory issued the No. 8 Gale or Storm Signal on the night of 13 November, the latest issuance of No. 8 Gale or Storm Signal in a year since 1946. Strong to gale force northeasterly winds affected most parts of the territory at first on 14 November. The outer rainbands of Toraji also brought squally showers to Hong Kong on that day. With the weakening of Toraji, local winds moderated gradually later on 14 November. Under the influence of the remnants of Toraji, the weather remained cloudy with occasional rain on 15 November. More than 30 millimetres of rainfall were generally recorded over the territory and rainfall even exceeded 70 millimetres over parts of Sha Tin and Tai Po Districts on 14 – 15 November.

It was mainly cloudy with a few showers on 16 – 17 November, with heavier showers in some areas on the night of 16 November. Around 10 millimetres of rainfall were recorded over many places of the territory and rainfall even exceeded 30 millimetres over the eastern part of Hong Kong Island and Kowloon East. A fresh to strong northeast monsoon affected Hong Kong on 18 November and there were sunny intervals. There were also a few light rain patches with the approach of Man-yi. Under the combined effects of a spring tide, northeast monsoon and Man-yi, water levels in Hong Kong were particularly high on the night of 18 November. The water levels of Quarry Bay, Tai O and Tai Po Kau reached 3.36, 3.36 and 3.52 metres above the Chart Datum respectively and they were all the highest on record for November. Minor flooding occurred in some low-lying areas including the banks of Shing Mun River, Lei Yue Mun, Tai O and Sha Tau Kok.

Under the influence of the northeast monsoon and a broad band of rain-bearing clouds, the weather was gloomy and rainy on 19 – 20 November. The rain was heavier at first on 20 November and more than 50 millimetres of rainfall were recorded over most parts of the territory. There were still a few rain patches at first on 21 November. With the band of clouds covering the coast of southern China thinning out gradually, there were sunny intervals in that afternoon and on 22 November. Affected by a fresh to strong easterly airstream, the weather was mainly cloudy with a few rain patches on 23 – 25 November. A cold front moved across the coastal areas of Guangdong in the small hours on 26 November. Locally, while there were a few showers at first, under the influence of the associated dry northeast monsoon, the weather turned fine and dry during the day and remained so till the end of the month. It was cool in the morning and at night on the last three days of the month with temperatures at the Observatory dropping to a minimum of 16.5 degrees on the morning of 30 November, the lowest of the month. Temperatures were appreciably lower in the New Territories.

Satellite image at 8 a.m. (Hong Kong Time) on 12 November, showing that four tropical cyclones occurred concurrently over the western North Pacific and the South China Sea, the first time in November since 1961

Minor flooding over the cycle tracks near Shing Mun River on the night of 18 November (Photo credit: 岳人 Geo Trekker)

Minor flooding in Tai O on the night of 18 November (Photo credit: Islands District Office)

Warnings and Signals issued in November 2024

Table 1.1   Tropical Cyclone Warning Signals

Name of Tropical Cyclone	Signal Number	Beginning Time		Ending Time
		Day/Month	HKT	Day/Month	HKT
YINXING	1	8 / 11	1240	9 / 11	1540
	3	9 / 11	1540	10 / 11	1020
	1	10 / 11	1020	10 / 11	1520
TORAJI	1	11 / 11	2220	13 / 11	1440
	3	13 / 11	1440	13 / 11	2310
	8 NE	13 / 11	2310	14 / 11	1020
	3	14 / 11	1020	14 / 11	2220
	1	14 / 11	2220	15 / 11	0120
MAN-YI	1	18 / 11	0640	19 / 11	2210

Table 1.2   Fire Danger Warnings

Colour	Beginning Time		Ending Time
	Day/Month	HKT	Day/Month	HKT
Red	30 / 10	0600	2 / 11	2230
Yellow	3 / 11	0730	3 / 11	1800
Red	6 / 11	1145	6 / 11	2110
Red	7 / 11	0730	8 / 11	2110
Red	26 / 11	0800	30 / 11	2330

Table 2   Figures and Departures from Normal - November 2024

Meteorological Element	Figure of the Month	Departure from Normal*
Mean Daily Maximum Air Temperature	25.3 degrees C	0.8 degrees above normal
Mean Air Temperature	23.0 degrees C	0.8 degrees above normal
Mean Daily Minimum Air Temperature	21.3 degrees C	1.0 degree above normal
Mean Dew Point Temperature	16.8 degrees C	0.1 degrees above normal
Mean Relative Humidity	70 %	2 % below normal
Mean Cloud Amount	71 %	13 % above normal
Total Rainfall	194.1 mm	154.8 mm above normal
Number of hours of Reduced VisibilityΔ	0 hours	100.5 hours below normal§
Total Bright Sunshine Duration	138.0 hours	34.3 hours below normal
Mean Daily Global Solar Radiation	11.36 Megajoule / square metre	0.9 Megajoule below normal
Total Evaporation	80.7 mm	14.4 mm below normal

Remarks :	All measurements were made at the Hong Kong Observatory except sunshine, solar radiation and evaporation which were recorded at King's Park Meteorological Station and visibility which was observed at the Hong Kong International Airport.
Δ	The visibility readings at the Hong Kong International Airport are based on hourly observations by professional meteorological observers in 2004 and before, and average readings over the 10-minute period before the clock hour of the visibility meter near the middle of the south runway from 2005 onwards. The change of the data source in 2005 is an improvement of the visibility assessment using instrumented observations following the international trend. Before 10 October 2007, the number of hours of reduced visibility at the Hong Kong International Airport in 2005 and thereafter displayed in this web page was based on hourly visibility observations by professional meteorological observers. Since 10 October 2007, the data have been revised using the average visibility readings over the 10-minute period before the clock hour, as recorded by the visibility meter near the middle of the south runway.
*   Departure from 1991 - 2020 climatological normal, except for number of hours of reduced visibility
§   Departure from mean value between 1997 and 2023

Remarks :

Extremely high: above 95th percentile Above normal: between 75th and 95th percentile Normal: between 25th and 75th percentile Below normal: between 5th and 25th percentile Extremely low: below 5th percentile Percentile and 5-day running average values are computed based on the data from 1991 to 2020