The Weather of June 2025 - A hot and relatively dry June

The weather of June 2025 was hotter and drier than usual in Hong Kong, mainly attributing to the stronger subtropical ridge covering southeastern China. With the easterly airstream prevailing over the coast of Guangdong replaced by a southerly airstream, it was hot with sunny periods and there were one or two showers in Hong Kong on the first two days of the month. When a trough of low pressure moved across the coast of Guangdong on 3 June, the local weather turned mainly cloudy with a few showers. An upper-air disturbance and a surface trough of low pressure brought showers to the northern part of the South China Sea and its coastal areas the next day. Locally, it was cloudy with showers. There were thunderstorms in the afternoon. More than 20 millimetres of rainfall were recorded over Lantau Island and the western part of the New Territories. While it was still mainly cloudy with one or two showers on 5 June, it became hot with sunny periods the next day, as the anticyclone aloft covering the coast of southeastern China strengthened gradually. Under the dominance of the anticyclone aloft, the local weather was generally fine with prolonged heat on 7 – 10 June. It was extremely hot on 10 June with the maximum temperature at the Observatory soaring to 35.6 degrees, levelling the record maximum for June since records began in 1884. The maximum temperature at Lau Fau Shan even reached 38.9 degrees, the highest record so far since the setup of the station in 1985.

Wutip formed as a tropical depression over the central part of the South China Sea on the night of 10 June. It tracked generally west-northwestward towards the Hainan Island and intensified gradually. Its outer rainbands occasionally brought squally showers to the northern part of the South China Sea and the coast of Guangdong. The Observatory issued the first tropical cyclone warning signal of the year on 11 June. Locally, the weather deteriorated gradually with a few squally showers that day. While there were sunny intervals during the day, there were also isolated thunderstorms in the afternoon. Wutip further intensified into a severe tropical storm on 12 June and gradually turned to a north-northeasterly track over Beibu Wan, skirting the western coast of Hainan Island and Leizhou Peninsula in the following two days. Under the influence of Wutip’s outer rainbands, there were squally showers locally on 12 – 14 June, with thunderstorms on 12 – 13 June. The showers were heavy with more than 30 millimetres of rainfall recorded over most parts of the territory on 13 June. The strong winds associated with Wutip affected the Pearl River Estuary and its vicinity on 15 June. Local winds were generally strong, occasionally reaching gale force on high ground. Winds moderated progressively later in the afternoon. While moving northeastwards further into inland areas, Wutip weakened gradually and finally degenerated into an area of low pressure on the evening of 15 June. Locally, there were still a few squally showers that day.

Under the influence of an active southwesterly airstream, showers and thunderstorms affected Hong Kong on 16 – 17 June. The showers were heavy with squally thunderstorms on 17 June. More than 30 millimetres of rainfall were generally recorded over the territory, and rainfall even exceeded 70 millimetres in the northern part of the New Territories, Tsuen Wan and Sai Kung Districts. With a southerly airstream affecting the coast of Guangdong, it was hot with sunny intervals in the following five days. Meanwhile, there were also occasional showers, with isolated thunderstorms on 19¬ – 20 June. More than 20 millimetres of rainfall were recorded over the eastern part of the New Territories on 20 June, and the eastern parts of Hong Kong Island and the New Territories on 21 June. While the southerly airstream continued to bring showers and isolated thunderstorms at first on 23 June, with an anticyclone aloft covering southern China, the weather became generally fine and very hot that afternoon, and remained so in the following two days. Besides, an area of low pressure over the central and northern parts of the South China Sea intensified into a tropical depression on 25 June and moved northwestward towards the eastern part of Hainan Island and Leizhou Peninsula. Its outer rainbands brought heavy showers and squally thunderstorms to Hong Kong the next day. Around 30 millimetres of rainfall were generally recorded over the territory, and rainfall even exceeded 50 millimetres over Hong Kong Island and Kowloon. A broad trough of low pressure and an upper-air disturbance affected the coast of Guangdong and brought showers and thunderstorms over the territory on 27 – 28 June. The showers were heavy in the small hours of 28 June, around 30 millimetres of rainfall were recorded over many places, and rainfall even exceeded 50 millimetres over Tai Po. With the broad trough of low pressure lingering over the coast of Guangdong, the weather remained mainly cloudy with showers and thunderstorms on the last two days of the month, with around 20 millimetres of rainfall recorded over Kowloon East and Sha Tin on 29 June.