August features record-breaking high temperatures
Attributed to the warmer-than-normal sea surface temperature over the northern part of the South China Sea and the southwesterly flow in the lower atmosphere over the coast of southern China, as well as the high temperature weather brought by the outer subsiding air of Tropical Cyclone Dolphin, Hong Kong was much hotter than usual in August 2026. The monthly mean temperature of 29.5 degrees, mean minimum temperature of 27.6 degrees and mean maximum temperature of 32.1 degrees were 0.8 degrees, 0.9 degrees and 0.8 degrees above their respective normals and were respectively one of the third, fourth and one of the eighth highest on record for August. With a total of nine consecutive very hot days from August 5 to 13, this was one of the longest consecutive very hot days on record for August. Among these, there were three consecutive extremely hot days from August 9 to 11, being the highest number of extremely hot days and also the longest consecutive extremely hot days for August. Mainly attributed to the high temperature weather in August, the summer of this year from June to August was slightly hotter than usual. The mean temperature of 28.9 degrees was 0.2 degrees above the normal for the same period. The monthly rainfall was 380.0 millimetres, about 16 per cent below the normal figure of 453.2 millimetres. The accumulated rainfall recorded in the first eight months of the year was 2 357.6 millimetres, about 23 per cent above the normal figure of 1 921.5 millimetres for the same period.
The broad trough of low pressure that affected the coast of Guangdong since late July continued its dominance into the early part of August. Locally, it was mainly cloudy with occasional heavy showers on the first three days of the month. There were also thunderstorms on August 1 and 2. Heavy showers brought more than 100 millimetres of rainfall to most parts of the territory on these three days, with rainfall even exceeding 200 millimetres over the eastern part of Hong Kong Island and New Territories East. Under the showers, the temperature at the Observatory dropped to a minimum of 25.0 degrees on August 3, the lowest of the month. The Observatory recorded maximum temperatures below 30.0 degrees for nine consecutive days from July 26 to August 3, a rare occurrence during the usual hot season in July and August, with the last occurrence dating back to August 1937. As the broad trough weakened on August 4, local weather improved with sunny periods and a few showers. Winds were weak in the following two days. Local weather was very hot with more sunshine on the afternoon of August 5 and the next day.
The outer subsiding air of Tropical Cyclone Dolphin and the subsequent southwesterly airstream brought generally fine and very hot weather to the territory in the next seven days. In particular, it was extremely hot from August 9 to 11. The temperature at the Observatory in the afternoon of August 9 soared to an all-time record high of 36.9 degrees. Meanwhile, the temperature at Sheung Shui reached 39.8 degrees, the highest ever recorded in Hong Kong since the establishment of automatic weather stations in the 1980s. Furthermore, the minimum temperature recorded at the Observatory in the morning of August 12 was 30.2 degrees, setting another record as the highest daily minimum temperature on record.
Under the influence of upper-air disturbances and a southwesterly airstream, local weather was mainly cloudy with occasional showers and squally thunderstorms on August 14 and in the morning of August 15. Showers were heavy at times. More than 40 millimetres of rainfall were recorded over many places on these two days, with rainfall even exceeding 100 millimetres over the Southern District. With the departure of the upper-air disturbances and the moderation of the southwesterly airstream, apart from isolated showers in the morning, local weather turned mainly fine and very hot on August 16. Winds were weak over Guangdong the next day. Locally, it was mainly cloudy with a few showers and thunderstorms, with showers heavier in some areas around noon due to heat-triggered thunderstorms, and more than 30 millimetres of rainfall was recorded.
A broad trough of low pressure brought showers and thunderstorms to the coast of Guangdong and the northern part of the South China Sea from August 18 to 24. Locally, under the combined effect of an area of low pressure within the broad trough over the northern part of the South China Sea and the ridge of high pressure over southeastern China, local easterly winds were stronger at night on August 18 and the next day. Under the influence of the broad trough, it was mainly cloudy with a few showers and sunny intervals from August 18 to 24. Showers were heavier on August 20 with around 10 millimetres of rainfall recorded over many places, and rainfall even exceeding 40 millimetres over Hong Kong Island and parts of Kowloon. There were also isolated thunderstorms on August 21 and 22. Moreover, the area of low pressure within the broad trough intensified gradually into a tropical cyclone over Beibu Wan on August 20 and was later named as Narra. Narra lingered over the vicinity of Beibu Wan in the next few days. It made landfall near Wuchuan on August 26 after moving across Leizhou Peninsula and weakened into a low pressure area.
Under the influence of an active southerly airstream and a subsequent trough of low pressure, local weather was cloudy with occasional showers and squally thunderstorms from August 25 to 27. More than 80 millimetres of rainfall were recorded over many places on these three days, with rainfall even exceeding 200 millimetres over the eastern part of Hong Kong. The heavy downpour also necessitated the issuance of the Red Rainstorm Warning Signal in the morning of August 27. Unfortunately, a man was found unconscious on a sampan near the Tseung Kwan O Cross Bay Link and later died in hospital, with initial reports suggesting he may have been struck by lightning. Although it was hot with sunny periods due to the moderation of the active southerly airstream, a broad trough of low pressure also brought a few showers and thunderstorms on August 28 and 29. Showers were heavy in some areas during the small hours on August 28 with about 70 millimetres of rainfall recorded over Tai Po and Lau Fau Shan. With the dominance of the broad trough over the coastal regions, showers increased gradually on the last two days of the month. Showers were heavy at times with a few squally thunderstorms on August 31. About 30 millimetres of rainfall were recorded over many places, and rainfall even exceeded 50 millimetres over Kowloon and parts of the New Territories West. Moreover, Tropical Cyclone Saudel made landfall over Zhejiang on August 28 and, over the following day or two, moved across eastern China and central China before weakening into an area of low pressure over southern China. Its remnant tracked southwards across the Leizhou Peninsula and Hainan Island on August 31, and in the evening of that day emerged over the waters just off the southeast coast of Hainan Island, where it re-intensified into a tropical depression. The Observatory subsequently issued the Standby Signal No. 1.
Thirteen tropical cyclones occurred over the South China Sea and the western North Pacific in August 2026.
Please refer to the following link for the latest monthly forecast: www.hko.gov.hk/en/wxinfo/month/month.htm.
Source: AI-created image
