The Weather of August 2022
2 September 2022
Mainly attributed to the rainfall associated with the tropical cyclone activity over the northern part of the South China Sea, the month was wetter than usual with the monthly rainfall of 614.8 millimetres, about 36 percent more than the normal figure of 453.2 millimetres. The accumulated rainfall recorded in the first eight months of the year was 1 827.8 millimetres, about 5 percent below the normal figure of 1 921.5 millimetres for the same period. The monthly mean temperature of 28.8 degrees was near the normal figure of 28.7 degrees. Owing to the record-breaking high temperature weather in July 2022, the summer of this year from June to August was much hotter than usual. The mean temperature of 29.2 degrees was one of the fourth highest on record for the same period.
Under the influence of an anticyclone aloft, the weather of Hong Kong was fine and very hot on the first day of the month. With plenty of sunshine, the maximum temperature at the Observatory soared to 35.7 degrees in the afternoon, the highest of the month. While it was mainly fine and very hot during the day on 2 August, convective activities triggered by high temperatures brought thundery showers to the territory in the evening. Meanwhile, an area of low pressure over the northeastern part of the South China Sea developed into a tropical depression on the night of 3 August. It moved generally west-northwestwards towards the east of the Pearl River Estuary. The tropical depression made landfall over the coast of Huidong and weakened into an area of low pressure over inland Guangdong on the afternoon of 4 August. Affected by the tropical depression and its remnant low pressure area, local weather was mainly cloudy with occasional heavy showers and squally thunderstorms on 3 – 5 August. More than 100 millimetres of rainfall were generally recorded over Hong Kong on these three days and rainfall even exceeded 200 millimetres over the eastern part of the territory. Under the rain, the temperature at the Observatory dropped to a minimum of 24.5 degrees on 5 August, the lowest of the month.
With the strengthening of the anticyclone aloft, showers abated gradually with sunny intervals on 6 August. Apart from isolated showers and squally thunderstorms, the weather was generally fine the next day. Affected by an area of low pressure over the central part of the South China Sea, local weather turned mainly cloudy with occasional showers and squally thunderstorms on 8 August. The area of low pressure developed gradually into a tropical depression on the early morning of 9 August and later named as Mulan. It moved generally northwards and intensified into a tropical storm during the day that day. It turned to move northwestwards afterwards. After skirting past the northeastern part of Hainan Island and southern tip of Leizhou Peninsula, Mulan entered Beibu Wan on the night of 10 August. It made landfall over the northern part of Vietnam and weakened into an area of low pressure over inland on 11 August. Affected by Mulan, it was windy in Hong Kong on 9 - 10 August. The outer rainbands of Mulan also brought occasional heavy showers, violent gusts and thunderstorms to the territory on these two days. More than 100 millimetres of rainfall were generally recorded over Hong Kong on 9 – 10 August and rainfall even exceeded 200 millimetres over parts of Lantau Island.
Under the influence of a broad trough of low pressure, local weather remained mainly cloudy with showers and a few squally thunderstorms on 11 – 12 August. The showers were heavier on the morning of 12 August. More than 50 millimetres of rainfall were generally recorded over the territory and rainfall even exceeded 70 millimetres over parts of Hong Kong Island, Kowloon and the northeastern part of the New Territories. Affected by an anticyclone aloft, there were sunny periods, isolated showers and thunderstorms on 13 August. Apart from a few isolated showers, the weather turned generally fine and very hot on 14 – 15 August.
Affected by an area of low pressure over the northeastern part of the South China Sea and the subsequent broad trough of low pressure, the weather of Hong Kong was a mixture of sunshine, showers and thunderstorms on 16 – 20 August. Showers were heavier on 17 August with more than 70 millimetres of rainfall recorded over parts of the New Territories. With an anticyclone aloft gradually covering southeastern China, local weather became mainly fine and very hot during the day on 21 August and remained so in the following two days.
Meanwhile, the area of low pressure over the seas east of Luzon developed into a tropical depression on 21 August and later named as Ma-on. It gradually intensified into a severe tropical storm on the morning of 23 August and moved across the northern part of Luzon. Ma-on entered the northeastern part of the South China Sea on that night and tracked generally northwestwards across the South China Sea towards the coast of western Guangdong on 24 August. It made landfall near Maoming and then weakened into a tropical storm the next morning. Ma-on moved across Guangdong and Guangxi and weakened into an area of low pressure over Indochina Peninsula on 26 August.
Under the influence of the subsiding air ahead of Ma-on, the weather of Hong Kong was mainly fine and very hot at first on 24 August. With Ma-on edging closer, the weather became cloudy with winds strengthening significantly later that day. The Observatory issued the second No.8 Gale or Storm Signal in this year that night. Strong to gale force winds generally affected the territory on the night of 24 August and at first on 25 August, with occasional storm force winds offshore and on high ground. With Ma-on departing from Hong Kong and weakening gradually over inland, local winds moderated quickly during the day on 25 August. The outer rainbands of Ma-on also brought occasional heavy squally showers to Hong Kong that day. More than 50 millimetres of rainfall were recorded over many places.
Affected by an anticyclone aloft, apart from isolated showers, it was generally fine and very hot on 26 – 28 August. Under light wind conditions, there were sunny periods and high temperature triggered thundery showers over parts of the territory on the last three days of the month.
Seven tropical cyclones occurred over the South China Sea and the western North Pacific in August 2022.
Details of issuance and cancellation of various warnings/signals in August are summarized in Tables 1.1 to 1.6. Monthly meteorological figures and departures from normal for August are tabulated in Table 2.
Mainly attributed to the rainfall associated with the tropical cyclone activity over the northern part of the South China Sea, the month was wetter than usual with the monthly rainfall of 614.8 millimetres, about 36 percent more than the normal figure of 453.2 millimetres. The accumulated rainfall recorded in the first eight months of the year was 1 827.8 millimetres, about 5 percent below the normal figure of 1 921.5 millimetres for the same period. The monthly mean temperature of 28.8 degrees was near the normal figure of 28.7 degrees. Owing to the record-breaking high temperature weather in July 2022, the summer of this year from June to August was much hotter than usual. The mean temperature of 29.2 degrees was one of the fourth highest on record for the same period.
Under the influence of an anticyclone aloft, the weather of Hong Kong was fine and very hot on the first day of the month. With plenty of sunshine, the maximum temperature at the Observatory soared to 35.7 degrees in the afternoon, the highest of the month. While it was mainly fine and very hot during the day on 2 August, convective activities triggered by high temperatures brought thundery showers to the territory in the evening. Meanwhile, an area of low pressure over the northeastern part of the South China Sea developed into a tropical depression on the night of 3 August. It moved generally west-northwestwards towards the east of the Pearl River Estuary. The tropical depression made landfall over the coast of Huidong and weakened into an area of low pressure over inland Guangdong on the afternoon of 4 August. Affected by the tropical depression and its remnant low pressure area, local weather was mainly cloudy with occasional heavy showers and squally thunderstorms on 3 – 5 August. More than 100 millimetres of rainfall were generally recorded over Hong Kong on these three days and rainfall even exceeded 200 millimetres over the eastern part of the territory. Under the rain, the temperature at the Observatory dropped to a minimum of 24.5 degrees on 5 August, the lowest of the month.
With the strengthening of the anticyclone aloft, showers abated gradually with sunny intervals on 6 August. Apart from isolated showers and squally thunderstorms, the weather was generally fine the next day. Affected by an area of low pressure over the central part of the South China Sea, local weather turned mainly cloudy with occasional showers and squally thunderstorms on 8 August. The area of low pressure developed gradually into a tropical depression on the early morning of 9 August and later named as Mulan. It moved generally northwards and intensified into a tropical storm during the day that day. It turned to move northwestwards afterwards. After skirting past the northeastern part of Hainan Island and southern tip of Leizhou Peninsula, Mulan entered Beibu Wan on the night of 10 August. It made landfall over the northern part of Vietnam and weakened into an area of low pressure over inland on 11 August. Affected by Mulan, it was windy in Hong Kong on 9 - 10 August. The outer rainbands of Mulan also brought occasional heavy showers, violent gusts and thunderstorms to the territory on these two days. More than 100 millimetres of rainfall were generally recorded over Hong Kong on 9 – 10 August and rainfall even exceeded 200 millimetres over parts of Lantau Island.
Under the influence of a broad trough of low pressure, local weather remained mainly cloudy with showers and a few squally thunderstorms on 11 – 12 August. The showers were heavier on the morning of 12 August. More than 50 millimetres of rainfall were generally recorded over the territory and rainfall even exceeded 70 millimetres over parts of Hong Kong Island, Kowloon and the northeastern part of the New Territories. Affected by an anticyclone aloft, there were sunny periods, isolated showers and thunderstorms on 13 August. Apart from a few isolated showers, the weather turned generally fine and very hot on 14 – 15 August.
Affected by an area of low pressure over the northeastern part of the South China Sea and the subsequent broad trough of low pressure, the weather of Hong Kong was a mixture of sunshine, showers and thunderstorms on 16 – 20 August. Showers were heavier on 17 August with more than 70 millimetres of rainfall recorded over parts of the New Territories. With an anticyclone aloft gradually covering southeastern China, local weather became mainly fine and very hot during the day on 21 August and remained so in the following two days.
Meanwhile, the area of low pressure over the seas east of Luzon developed into a tropical depression on 21 August and later named as Ma-on. It gradually intensified into a severe tropical storm on the morning of 23 August and moved across the northern part of Luzon. Ma-on entered the northeastern part of the South China Sea on that night and tracked generally northwestwards across the South China Sea towards the coast of western Guangdong on 24 August. It made landfall near Maoming and then weakened into a tropical storm the next morning. Ma-on moved across Guangdong and Guangxi and weakened into an area of low pressure over Indochina Peninsula on 26 August.
Under the influence of the subsiding air ahead of Ma-on, the weather of Hong Kong was mainly fine and very hot at first on 24 August. With Ma-on edging closer, the weather became cloudy with winds strengthening significantly later that day. The Observatory issued the second No.8 Gale or Storm Signal in this year that night. Strong to gale force winds generally affected the territory on the night of 24 August and at first on 25 August, with occasional storm force winds offshore and on high ground. With Ma-on departing from Hong Kong and weakening gradually over inland, local winds moderated quickly during the day on 25 August. The outer rainbands of Ma-on also brought occasional heavy squally showers to Hong Kong that day. More than 50 millimetres of rainfall were recorded over many places.
Affected by an anticyclone aloft, apart from isolated showers, it was generally fine and very hot on 26 – 28 August. Under light wind conditions, there were sunny periods and high temperature triggered thundery showers over parts of the territory on the last three days of the month.
Seven tropical cyclones occurred over the South China Sea and the western North Pacific in August 2022.
Details of issuance and cancellation of various warnings/signals in August are summarized in Tables 1.1 to 1.6. Monthly meteorological figures and departures from normal for August are tabulated in Table 2.
Warnings and Signals issued in August 2022
| Name of Tropical Cyclone |
Signal Number |
Beginning Time | Ending Time | ||
|---|---|---|---|---|---|
| Day/Month | HKT | Day/Month | HKT | ||
| no name | 1 | 3 / 8 | 2210 | 4 / 8 | 1440 |
| MULAN | 1 | 9 / 8 | 0340 | 9 / 8 | 1125 |
| 3 | 9 / 8 | 1125 | 10 / 8 | 1820 | |
| MA-ON | 1 | 23 / 8 | 2110 | 24 / 8 | 1240 |
| 3 | 24 / 8 | 1240 | 24 / 8 | 1925 | |
| 8 NE | 24 / 8 | 1925 | 25 / 8 | 0140 | |
| 8 SE | 25 / 8 | 0140 | 25 / 8 | 0920 | |
| 3 | 25 / 8 | 0920 | 25 / 8 | 1410 | |
| 1 | 25 / 8 | 1410 | 25 / 8 | 1610 | |
| Beginning Time | Ending Time | ||
|---|---|---|---|
| Day/Month | HKT | Day/Month | HKT |
| 11 / 8 | 0210 | 11 / 8 | 0620 |
| 20 / 8 | 0045 | 20 / 8 | 0945 |
| Colour | Beginning Time | Ending Time | ||
|---|---|---|---|---|
| Day/Month | HKT | Day/Month | HKT | |
| Amber | 3 / 8 | 1530 | 3 / 8 | 1700 |
| Amber | 5 / 8 | 0408 | 5 / 8 | 0930 |
| Amber | 5 / 8 | 1305 | 5 / 8 | 1735 |
| Amber | 12 / 8 | 0840 | 12 / 8 | 1215 |
| Amber | 17 / 8 | 1610 | 17 / 8 | 1815 |
| Beginning Time | Ending Time | ||
|---|---|---|---|
| Day/Month | HKT | Day/Month | HKT |
| 2 / 8 | 1232 | 2 / 8 | 1345 |
| 2 / 8 | 1750 | 2 / 8 | 2400 |
| 3 / 8 | 0427 | 3 / 8 | 1030 |
| 3 / 8 | 1255 | 3 / 8 | 2000 |
| 4 / 8 | 0840 | 4 / 8 | 1000 |
| 4 / 8 | 1337 | 4 / 8 | 1700 |
| 5 / 8 | 0325 | 5 / 8 | 0930 |
| 5 / 8 | 1032 | 5 / 8 | 1800 |
| 6 / 8 | 1000 | 6 / 8 | 1100 |
| 6 / 8 | 1135 | 6 / 8 | 1700 |
| 7 / 8 | 1207 | 7 / 8 | 1330 |
| 7 / 8 | 2021 | 7 / 8 | 2130 |
| 7 / 8 | 2200 | 7 / 8 | 2300 |
| 8 / 8 | 0101 | 8 / 8 | 0345 |
| 8 / 8 | 0605 | 8 / 8 | 1645 |
| 8 / 8 | 1740 | 9 / 8 | 0345 |
| 9 / 8 | 0630 | 9 / 8 | 2130 |
| 10 / 8 | 0430 | 10 / 8 | 0630 |
| 10 / 8 | 1704 | 10 / 8 | 2330 |
| 11 / 8 | 1015 | 11 / 8 | 1800 |
| 12 / 8 | 0404 | 12 / 8 | 0515 |
| 12 / 8 | 0732 | 12 / 8 | 1300 |
| 13 / 8 | 1440 | 13 / 8 | 1540 |
| 16 / 8 | 0612 | 16 / 8 | 0715 |
| 17 / 8 | 0143 | 17 / 8 | 0615 |
| 17 / 8 | 1531 | 17 / 8 | 1930 |
| 20 / 8 | 1310 | 20 / 8 | 1550 |
| 21 / 8 | 0232 | 21 / 8 | 0600 |
| 21 / 8 | 1825 | 21 / 8 | 2000 |
| 23 / 8 | 2000 | 23 / 8 | 2200 |
| 25 / 8 | 1650 | 25 / 8 | 2100 |
| 28 / 8 | 1318 | 28 / 8 | 1530 |
| 29 / 8 | 1316 | 29 / 8 | 1600 |
| 30 / 8 | 1350 | 30 / 8 | 1645 |
| 31 / 8 | 1114 | 31 / 8 | 1730 |
| Beginning Time | Ending Time | ||
|---|---|---|---|
| Day/Month | HKT | Day/Month | HKT |
| 31 / 7 | 0930 | 2 / 8 | 2025 |
| 13 / 8 | 1345 | 15 / 8 | 1845 |
| 16 / 8 | 1445 | 16 / 8 | 1830 |
| 21 / 8 | 1145 | 24 / 8 | 1715 |
| 26 / 8 | 0945 | 30 / 8 | 1650 |
| Beginning Time | Ending Time | ||
|---|---|---|---|
| Day/Month | HKT | Day/Month | HKT |
| 17 / 8 | 1550 | 17 / 8 | 1815 |
| Meteorological Element | Figure of the Month | Departure from Normal* |
|---|---|---|
| Mean Daily Maximum Air Temperature | 31.9 degrees C | 0.6 degree above normal |
| Mean Air Temperature | 28.8 degrees C | 0.1 degree above normal |
| Mean Daily Minimum Air Temperature | 26.8 degrees C | 0.1 degree above normal |
| Mean Dew Point Temperature | 25.4 degrees C | 0.3 degree above normal |
| Mean Relative Humidity | 82 % | 1 % above normal |
| Mean Cloud Amount | 71 % | 1 % above normal |
| Total Rainfall | 614.8 mm | 161.6 mm above normal |
| Number of hours of Reduced VisibilityΔ | 2 hours | 38.9 hours below normal§ |
| Total Bright Sunshine Duration | 167.7 hours | 14.4 hours below normal |
| Mean Daily Global Solar Radiation | 16.22 Megajoule / square metre | 0.49 Megajoule above normal |
| Total Evaporation | 99.3 mm | 30.4 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. |
| * | Departure from 1991 - 2020 climatological normal, except for number of hours of reduced visibility |
| § | Departure from mean value between 1997 and 2021 |
| 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 |
