After a very dry first half of the year, more significant rainfall eventually returned to Hong Kong in July 2025, mainly due to the passage of the remnant of tropical cyclone Danas in early July and typhoon Wipha in mid-July, as well as showers associated with troughs of low pressure and active southwesterly airstreams during the month. Also, the strike of Wipha necessitated the issuance of the Hurricane Signal No. 10 on July 20. The monthly rainfall was 601.7 millimetres, about 56 per cent above the normal of 385.8 millimetres. However, with the rainfall well below normal in the first half of the year, the accumulated rainfall recorded in the first seven months of the year was only 1 046.1 millimetres, still a deficit of 29 per cent compared to the normal of 1 468.2 millimetres for the same period. The month was also warmer than usual with the monthly mean maximum temperature of 32.4 degrees, 0.8 degrees above the normal and one of the ninth highest on record for July. The monthly mean temperature of 29.5 degrees and monthly mean minimum temperature of 27.4 degrees were 0.6 degrees and 0.5 degrees above their respective normals.

     A broad trough of low pressure and upper-air disturbances brought showers and thunderstorms to Hong Kong on the first day of the month. More than 40 millimetres of rainfall were recorded over Lamma Island and the northeastern part of the New Territories. With the establishment of an anticyclone aloft over southern China, apart from isolated showers and thunderstorms, the weather was generally fine and very hot in the following three days.

     Moreover, Danas formed as a tropical depression over the northeastern part of the South China Sea on the morning of July 4 and moved northwestwards slowly. It turned to move northeastwards on the next day. Danas intensified progressively into a severe typhoon and made landfall over the western coast of Taiwan on the night of July 6. Danas then entered the East China Sea and weakened progressively into a tropical storm. Locally, apart from isolated showers and squally thunderstorms, it was sunny and extremely hot from July 5 to 7. Temperatures over many places rose to around 35 degrees. On July 7, the maximum temperature recorded at the Observatory was 34.3 degrees, the hottest Moderate Heat ever recorded.

     Under the influence of a southwesterly airstream, the weather remained very hot with a mixture of sunshine and showers on July 8 and 9. Meanwhile, Danas made a second sharp turn over the East China Sea on July 8, and made landfall near Wenzhou, Zhejiang, that night. It finally degenerated into an area of low pressure over Fujian on the night of July 9. The remnant of Danas continued to track southwestwards and edge closer to Guangdong. Under the influence of the remnant of Danas and an active southwest monsoon, there were outbreaks of showers and thunderstorms on the night of July 9, and from July 10 to 12. Showers were particularly heavy on the night of July 9 and 10, and more than 100 millimetres of rainfall were generally recorded over the territory. Rainfall even exceeded 200 millimetres over Tsuen Wan and Tsing Yi. The Red Rainstorm Warning was issued three times during the period. Under the heavy rain, temperatures at the Hong Kong Observatory also fell to a minimum of 25.0 degrees on the morning of July 10, the lowest of the month. While there were still showers and thunderstorms from July 13 to 15, it was also very hot with sunny periods under the influence of an anticyclone aloft.

     The weather was generally fine and extremely hot during the days on July 16 and 17. Under light wind conditions, heavy showers and thunderstorms triggered by high temperatures affected Hong Kong during the day on July 18. More than 30 millimetres of rainfall were recorded over many places and a severe rainstorm of more than 100 millimetres of hourly rainfall were recorded over Yuen Long District at noon.

     Furthermore, Wipha formed as a tropical depression over the seas east of the Philippines on July 16. It then tracked northwestwards towards the Luzon Strait and intensified into a tropical storm on July 18. Wipha moved across the northern part of the South China Sea on July 19 and intensified into a typhoon at night. It skirted about 60 kilometres south of the Hong Kong Observatory towards noon on July 20 and moved across the vicinity of the coast of western Guangdong and towards Beibu Wan afterwards.

     Locally, it was very hot with sunny periods on July 19 under the influence of Wipha's outer subsiding air. With Wipha edging closer to the coast of Guangdong gradually, its outer rainbands started to bring squally showers and thunderstorms to the territory at night. As Wipha came quite close to Hong Kong on July 20, many places were affected by storm to hurricane force winds during the day. The maximum 60-minute mean wind speeds recorded at Waglan Island and Cheung Chau were 131km per hour and 115km per hour respectively. With Wipha departing from Hong Kong and weakening gradually, local winds moderated later on July 20. More than 70 millimetres of rainfall were generally recorded over Hong Kong on July 20, and rainfall even exceeded 200 millimetres over parts of the territory. According to preliminary reports, more than 33 people were injured during the passage of Wipha. There were at least 2 284 reports of fallen trees, seven reports of flooding and five reports of collapsed scaffolding. More than 500 flights were cancelled at Hong Kong International Airport. Under the influence of the outer rainbands associated with Wipha, there were still occasional showers and squally thunderstorms on July 21.

     A broad trough of low pressure affected the coast of Guangdong and the northern part of the South China Sea on July 22. Locally, the heavy showers on the night of July 22 generally brought more than 40 millimetres of rainfall to the territory. Local weather was generally fine with prolonged heat during the day from July 23 to 27. The maximum temperature at the Observatory rose to 35.2 degrees on the afternoon of July 26, the highest of the month. High temperatures also triggered showers and squally thunderstorms from July 23 to 25. Heavy thundery showers on the evening of July 25 brought more than 50 millimetres of rainfall to parts of the territory, and rainfall even exceeded 90 millimetres over Sai Kung District. Violent gusts of around 110km per hour were recorded at Sai Kung.

     While it was very hot with sunny intervals at first on July 28, with an area of thundery showers edging closer to the coastal areas, there were occasional showers and a few thunderstorms later on that day. A broad trough of low pressure brought occasional showers and thunderstorms to Hong Kong on July 29 and 30. The heavy downpour on the morning of July 29 necessitated the issuance of the first Black Rainstorm Warning of the year. More than 70 millimetres of rainfall were recorded over many places, and rainfall even exceeded 200 millimetres over the eastern part of Hong Kong Island, Sai Kung District and Lamma Island. There were eight reports of flooding in Hong Kong. Under the influence of a southwesterly airstream, the weather of Hong Kong was a mixture of sunshine and showers on the last day of the month.

     Eight tropical cyclones occurred over the South China Sea and the western North Pacific in July 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 July are tabulated in Table 2.

Ends/Monday, August 4, 2025
Issued at HKT 17:00

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