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The Weather of July 2025 - A rainy July with the strike of Wipha

4 August 2025

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 showery activities associated with troughs of low pressure and active southwesterly airstreams in the month. Also, the strike of Wipha necessitated the issuance of the Hurricane Signal No. 10 on 20 July. The monthly rainfall was 601.7 millimetres, about 56 percent above the normal of 385.8 millimetres. However, with the well below normal rainfall in the first half of the year, the accumulated rainfall recorded in the first seven months of the year was only 1046.1 millimetres, still a deficit of 29 percent compared to the normal of 1468.2 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. 

Besides, Danas formed as a tropical depression over the northeastern part of the South China Sea on the morning of 4 July 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 6 July. 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 on 5 – 7 July. Temperatures over many places rose to around 35 degrees. On 7 July, 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 8 – 9 July. Meanwhile, Danas made the second sharp turn over the East China Sea on 8 July, and made landfall near Wenzhou, Zhejiang that night. It finally degenerated into an area of low pressure over Fujian on the night of 9 July. 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 9 July and 10 – 12 July. The showers were particularly heavy on the night of 9 July and 10 July and more than 100 millimetres of rainfall were generally recorded over the territory. Rainfall even exceeded 200 millimetres over Tsuen Wan and Tsing Yi. 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 10 July, the lowest of the month. While there were still showers and thunderstorms on 13 – 15 July, 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 16 – 17 July. Under light winds conditions, heavy showers and thunderstorms triggered by high temperatures affected Hong Kong during the day on 18 July. More than 30 millimetres of rainfall were recorded over many places and severe rainstorm of more than 100 millimetres of hourly rainfall were recorded over Yuen Long District at noon.

Besides, Wipha formed as a tropical depression over the seas east of the Philippines on 16 July. It then tracked northwestwards towards Luzon Strait and intensified into a tropical storm on 18 July. Wipha moved across the northern part of the South China Sea on 19 July and intensified into a typhoon at night. It skirted about 60 kilometres south of the Hong Kong Observatory towards noon on 20 July 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 19 July 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 20 July, 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 131 km/h and 115 km/h respectively. With Wipha departing from Hong Kong and weakening gradually, local winds moderated later on 20 July. More than 70 millimetres of rainfall were generally recorded over Hong Kong on 20 July, 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 the Hong Kong International Airport. Under the influence of the outer rainbands associated with Wipha, there were still occasional showers and squally thunderstorms on 21 July. 

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

While it was very hot with sunny intervals at first on 28 July, 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 29 – 30 July. The heavy downpour on the morning of 29 July necessitated the issuance of the first Black Rainstorm Warning in 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.

 
Fallen trees in many parts of the territory during the passage of Wipha
(Courtesy of Fire Services Department (top left and right), 張銘輝/CWOS (bottom left) and Dr. T. C. Lee (bottom right))



Flooded roads at Wong Tai Sin (top) and Tai Po (bottom) on 20 July 2025 during the passage of Wipha
(Courtesy of Drainage Services Department)



Flooding at Chai Wan during the rainstorm of 29 July 2025
(Courtesy of HK01 / Photos by Liu Ngan Hung)


Details of issuance and cancellation of various warnings/signals in the month are summarised in Tables 1.1 to 1.5.  Monthly meteorological figures and departures from normal for July are tabulated in Table 2.

Warnings and Signals issued in July 2025

Table 1.1   Tropical Cyclone Warning Signals
Name of
Tropical Cyclone
Signal
Number
Beginning Time Ending Time
Day/Month HKT Day/Month HKT
DANAS 1 4 / 7 1220 6 / 7 1420
WIPHA 1 19 / 7 0220 19 / 7 1420
3 19 / 7 1420 20 / 7 0020
8 NE 20 / 7 0020 20 / 7 0720
9 20 / 7 0720 20 / 7 0920
10 20 / 7 0920 20 / 7 1610
8 SE 20 / 7 1610 20 / 7 1940
3 20 / 7 1940 21 / 7 0320
1 21 / 7 0320 21 / 7 0510


Table 1.2   Rainstorm Warning Signals
Colour Beginning Time Ending Time
Day/Month HKT Day/Month HKT
Amber 30 / 6 2355 1 / 7 0110
Amber 9 / 7 2300 9 / 7 2345
Red 9 / 7 2345 10 / 7 0045
Amber 10 / 7 0045 10 / 7 0140
Amber 10 / 7 0835 10 / 7 0936
Red 10 / 7 0936 10 / 7 1040
Amber 10 / 7 1040 10 / 7 1240
Red 10 / 7 1240 10 / 7 1530
Amber 10 / 7 1530 10 / 7 2000
Amber 18 / 7 1115 18 / 7 1300
Amber 20 / 7 1510 20 / 7 1545
Red 20 / 7 1545 20 / 7 1700
Amber 20 / 7 1700 20 / 7 1815
Amber 22 / 7 2000 22 / 7 2345
Amber 25 / 7 1910 25 / 7 1940
Red 25 / 7 1940 25 / 7 2040
Amber 25 / 7 2040 25 / 7 2110
Amber 29 / 7 0805 29 / 7 0840
Red 29 / 7 0840 29 / 7 0910
Black 29 / 7 0910 29 / 7 1105
Red 29 / 7 1105 29 / 7 1145
Amber 29 / 7 1145 29 / 7 1415


Table 1.3   Thunderstorm Warning
Beginning Time Ending Time
Day/Month HKT Day/Month HKT
30 / 6 2045 1 / 7 0400
1 / 7 0555 1 / 7 1800
2 / 7 0100 2 / 7 0350
2 / 7 1109 2 / 7 1330
3 / 7 0343 3 / 7 0515
5 / 7 1347 5 / 7 1900
7 / 7 0507 7 / 7 0715
8 / 7 1037 8 / 7 1400
8 / 7 2347 9 / 7 0100
9 / 7 0246 9 / 7 0400
9 / 7 0658 9 / 7 1130
9 / 7 1810 9 / 7 1930
9 / 7 2200 10 / 7 2045
11 / 7 0600 11 / 7 0830
11 / 7 2350 12 / 7 1700
14 / 7 0648 14 / 7 1030
15 / 7 0700 15 / 7 0830
15 / 7 1209 15 / 7 1400
15 / 7 1524 15 / 7 1630
18 / 7 0340 18 / 7 0730
18 / 7 1000 18 / 7 1700
19 / 7 1830 19 / 7 2300
20 / 7 0100 20 / 7 0500
20 / 7 0620 20 / 7 2200
21 / 7 0803 21 / 7 1930
22 / 7 1516 22 / 7 1700
22 / 7 2055 23 / 7 0030
23 / 7 0430 23 / 7 0630
23 / 7 1710 23 / 7 1830
24 / 7 1311 24 / 7 2000
25 / 7 1340 25 / 7 2230
28 / 7 1544 28 / 7 2200
29 / 7 0120 29 / 7 1530
30 / 7 1805 30 / 7 1940
31 / 7 0115 31 / 7 0610
31 / 7 0950 31 / 7 1555


Table 1.4   Very Hot Weather Warning
Beginning Time Ending Time
Day/Month HKT Day/Month HKT
2 / 7 1330 9 / 7 2300
13 / 7 1230 18 / 7 1105
19 / 7 0730 19 / 7 1935
23 / 7 1400 23 / 7 1730
24 / 7 0645 25 / 7 1915
26 / 7 0645 28 / 7 1715
30 / 7 1310 30 / 7 1800


Table 1.5   Special Announcement on Flooding
in the Northern New Territories
Beginning Time Ending Time
Day/Month HKT Day/Month HKT
9 / 7 2355 10 / 7 0225
10 / 7 1240 10 / 7 1510
18 / 7 1120 18 / 7 1710
20 / 7 1550 20 / 7 2120
29 / 7 1327 29 / 7 1600


Table 2   Figures and Departures from Normal - July 2025
Meteorological Element Figure of the Month Departure from Normal*
Mean Daily Maximum Air Temperature 32.4 degrees C 0.8 degrees above normal
Mean Air Temperature 29.5 degrees C 0.6 degrees above normal
Mean Daily Minimum Air Temperature 27.4 degrees C 0.5 degrees above normal
Mean Dew Point Temperature 25.7 degrees C 0.5 degrees above normal
Mean Relative Humidity 81 % normal
Mean Cloud Amount 80 % 8 % above normal
Total Rainfall 601.7 mm 215.9 mm above normal
Number of hours of Reduced VisibilityΔ 0 hours 10.8 hours below normal§
Total Bright Sunshine Duration 191.9 hours 5.4 hours below normal
Mean Daily Global Solar Radiation 17.44 Megajoule / square metre 0.22 Megajoule above normal
Total Evaporation 117.9 mm 24.1 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 2024

Daily values of selected meteorological elements for Hong Kong for July 2025

The percentile map of mean temperature of July 2025

  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


Extract of Meteorological Observations in Hong Kong for July 2025