The Weather of July 2022
2 August 2022
With a stronger than usual subtropical ridge persisting over southern China and bringing prolonged high temperature weather to the region in the month, July 2022 was the hottest month in Hong Kong since records began in 1884, breaking the previous record set in July 2020. The monthly mean temperature of 30.3 degrees and monthly mean minimum temperature of 28.4 degrees were 1.4 degrees and 1.5 degrees above their normals and both were the highest of the correspondingly monthly mean values on record. Moreover, the monthly mean maximum temperature of 33.3 degrees was 1.7 degrees above the normal and one of the highest on record. There were 10 days with daily maximum temperatures at the Hong Kong Observatory equal to or higher than 35.0 degrees, the highest number in a month on record and also breaking the record for a year. With a total of 25 hot nights, July 2022 was the month with the highest number of hot nights on record and the 21 consecutive hot nights that started from 9 July also set a new record. Moreover, there were 21 very hot days in the month, the highest number of very hot days in a month on record. With fine weather prevailing for most of the time in the month, July 2022 was also much drier than usual. The total monthly rainfall was only 158.5 millimetres, about 41 percent of the normal figure of 385.8 millimetres. The accumulated rainfall for the first seven months of the year was 1213.0 millimetres, about 17 percent below the normal figure of 1468.2 millimetres.
Severe Tropical Storm Chaba over the northern part of the South China Sea moved generally north-northwestwards towards the coast of western Guangdong on 1 July. It further intensified into a typhoon the next morning. Chaba made landfall near Maoming and weakened into a severe tropical storm that evening. It then moved across inland Guangdong and Guangxi and weakened gradually into a low pressure area over inland on 3 July. With the approach of Chaba, local winds strengthened significantly later on 1 July, necessitating the issuance of the first No.8 Gale or Storm Signal in this year and also the first time on the HKSAR Establishment Day. Strong to gale force winds generally affected the territory on 2 July, with occasional storm force winds offshore and on high ground at first. With Chaba departing from Hong Kong and weakening gradually over inland, local winds moderated gradually later in that afternoon. The outer rainbands of Chaba also brought heavy squally showers and thunderstorms to Hong Kong on 1 – 2 July. More than 100 millimetres of rainfall were generally recorded over Hong Kong on these two days and rainfall even exceeded 150 millimetres in parts of Tsuen Wan, Sha Tin, Kowloon City and Wan Chai Districts. Under the rain, the temperature at the Hong Kong Observatory fell to the month’s lowest of 25.4 degrees on 1 July. The weather of Hong Kong remained mainly cloudy with occasional showers and squalls on 3 July.
Affected by the remnant of Chaba and subsequently a strong southwest monsoon, the weather of Hong Kong was cloudy with showers and thunderstorms on 4 – 6 July. The showers were particularly heavy in some areas of Tai Po and North Districts with more than 70 millimetres of rainfall recorded on 5 July. Under the influence of a southerly airstream, there were sunny intervals with a few showers and isolated thunderstorms on 7 July.
With the subtropical ridge extending westwards and dominating over southern China, apart from a few showers, there was a long spell of generally fine and very hot weather in Hong Kong starting from 8 July to 29 July. With plenty of sunshine, the maximum temperature at the Observatory reached 34.9 degrees on 23 July, the hottest Great Heat on record. The maximum temperature at the Observatory soared further to 36.1 degrees on 24 July, the highest of the month and the highest maximum temperature for July on record. The maximum temperature recorded at Sheung Shui on that day even reached 39.0 degrees, the highest record since the station was established in 2004. Moreover, the daily mean temperature at the Observatory was 32.0 degrees on 24 and 25 July, both were the highest on record for July. The daily minimum temperature of 29.9 degrees on 25 July was also the highest on record for July.
Under light wind and unstable atmospheric conditions, there were thundery showers development over Hong Kong on 30 July. The showers were heavy at times with intense thunderstorms and incessant lightning in the morning. More than 30 millimetres of rainfall were recorded over some places and rainfall even exceeded 70 millimetres over Sai Kung. During the inclement weather in that morning, a person died after being struck by lightning while hiking in Sha Tin. Affected by an anticyclone aloft, apart from isolated showers and thunderstorms, the weather became generally fine and very hot again on the last day of the month.
Four tropical cyclones occurred over the South China Sea and the western North Pacific in July 2022.
With a stronger than usual subtropical ridge persisting over southern China and bringing prolonged high temperature weather to the region in the month, July 2022 was the hottest month in Hong Kong since records began in 1884, breaking the previous record set in July 2020. The monthly mean temperature of 30.3 degrees and monthly mean minimum temperature of 28.4 degrees were 1.4 degrees and 1.5 degrees above their normals and both were the highest of the correspondingly monthly mean values on record. Moreover, the monthly mean maximum temperature of 33.3 degrees was 1.7 degrees above the normal and one of the highest on record. There were 10 days with daily maximum temperatures at the Hong Kong Observatory equal to or higher than 35.0 degrees, the highest number in a month on record and also breaking the record for a year. With a total of 25 hot nights, July 2022 was the month with the highest number of hot nights on record and the 21 consecutive hot nights that started from 9 July also set a new record. Moreover, there were 21 very hot days in the month, the highest number of very hot days in a month on record. With fine weather prevailing for most of the time in the month, July 2022 was also much drier than usual. The total monthly rainfall was only 158.5 millimetres, about 41 percent of the normal figure of 385.8 millimetres. The accumulated rainfall for the first seven months of the year was 1213.0 millimetres, about 17 percent below the normal figure of 1468.2 millimetres.
Severe Tropical Storm Chaba over the northern part of the South China Sea moved generally north-northwestwards towards the coast of western Guangdong on 1 July. It further intensified into a typhoon the next morning. Chaba made landfall near Maoming and weakened into a severe tropical storm that evening. It then moved across inland Guangdong and Guangxi and weakened gradually into a low pressure area over inland on 3 July. With the approach of Chaba, local winds strengthened significantly later on 1 July, necessitating the issuance of the first No.8 Gale or Storm Signal in this year and also the first time on the HKSAR Establishment Day. Strong to gale force winds generally affected the territory on 2 July, with occasional storm force winds offshore and on high ground at first. With Chaba departing from Hong Kong and weakening gradually over inland, local winds moderated gradually later in that afternoon. The outer rainbands of Chaba also brought heavy squally showers and thunderstorms to Hong Kong on 1 – 2 July. More than 100 millimetres of rainfall were generally recorded over Hong Kong on these two days and rainfall even exceeded 150 millimetres in parts of Tsuen Wan, Sha Tin, Kowloon City and Wan Chai Districts. Under the rain, the temperature at the Hong Kong Observatory fell to the month’s lowest of 25.4 degrees on 1 July. The weather of Hong Kong remained mainly cloudy with occasional showers and squalls on 3 July.
Affected by the remnant of Chaba and subsequently a strong southwest monsoon, the weather of Hong Kong was cloudy with showers and thunderstorms on 4 – 6 July. The showers were particularly heavy in some areas of Tai Po and North Districts with more than 70 millimetres of rainfall recorded on 5 July. Under the influence of a southerly airstream, there were sunny intervals with a few showers and isolated thunderstorms on 7 July.
With the subtropical ridge extending westwards and dominating over southern China, apart from a few showers, there was a long spell of generally fine and very hot weather in Hong Kong starting from 8 July to 29 July. With plenty of sunshine, the maximum temperature at the Observatory reached 34.9 degrees on 23 July, the hottest Great Heat on record. The maximum temperature at the Observatory soared further to 36.1 degrees on 24 July, the highest of the month and the highest maximum temperature for July on record. The maximum temperature recorded at Sheung Shui on that day even reached 39.0 degrees, the highest record since the station was established in 2004. Moreover, the daily mean temperature at the Observatory was 32.0 degrees on 24 and 25 July, both were the highest on record for July. The daily minimum temperature of 29.9 degrees on 25 July was also the highest on record for July.
Under light wind and unstable atmospheric conditions, there were thundery showers development over Hong Kong on 30 July. The showers were heavy at times with intense thunderstorms and incessant lightning in the morning. More than 30 millimetres of rainfall were recorded over some places and rainfall even exceeded 70 millimetres over Sai Kung. During the inclement weather in that morning, a person died after being struck by lightning while hiking in Sha Tin. Affected by an anticyclone aloft, apart from isolated showers and thunderstorms, the weather became generally fine and very hot again on the last day of the month.
Four tropical cyclones occurred over the South China Sea and the western North Pacific in July 2022.
Details of issuance and cancellation of various warnings/signals in the month are summarized in Tables 1.1 to 1.5. Monthly meteorological figures and departures from normal for July are tabulated in Table 2. Summary of record-breaking high temperature events in July 2022 are tabulated in Table 3.
Warnings and Signals issued in July 2022
| Name of Tropical Cyclone |
Signal Number |
Beginning Time | Ending Time | ||
|---|---|---|---|---|---|
| Day/Month | HKT | Day/Month | HKT | ||
| CHABA | 3 | 30 / 6 | 2240 | 1 / 7 | 1910 |
| 8 SE | 1 / 7 | 1910 | 2 / 7 | 1620 | |
| 3 | 2 / 7 | 1620 | 3 / 7 | 1410 | |
| 1 | 3 / 7 | 1410 | 3 / 7 | 1940 | |
| Beginning Time | Ending Time | ||
|---|---|---|---|
| Day/Month | HKT | Day/Month | HKT |
| 3 / 7 | 1950 | 5 / 7 | 0745 |
| Colour | Beginning Time | Ending Time | ||
|---|---|---|---|---|
| Day/Month | HKT | Day/Month | HKT | |
| Amber | 1 / 7 | 0050 | 1 / 7 | 0210 |
| Amber | 1 / 7 | 1515 | 1 / 7 | 1715 |
| Amber | 30 / 7 | 1000 | 30 / 7 | 1130 |
| Beginning Time | Ending Time | ||
|---|---|---|---|
| Day/Month | HKT | Day/Month | HKT |
| 1 / 7 | 0047 | 1 / 7 | 0150 |
| 1 / 7 | 1225 | 1 / 7 | 1630 |
| 2 / 7 | 0205 | 2 / 7 | 0730 |
| 2 / 7 | 1152 | 2 / 7 | 1400 |
| 2 / 7 | 1815 | 2 / 7 | 2330 |
| 3 / 7 | 0015 | 3 / 7 | 0600 |
| 5 / 7 | 1320 | 5 / 7 | 1830 |
| 6 / 7 | 0420 | 6 / 7 | 0545 |
| 6 / 7 | 0820 | 6 / 7 | 1030 |
| 6 / 7 | 1050 | 6 / 7 | 1300 |
| 7 / 7 | 0420 | 7 / 7 | 0715 |
| 7 / 7 | 1226 | 7 / 7 | 1630 |
| 7 / 7 | 1647 | 7 / 7 | 1800 |
| 16 / 7 | 0902 | 16 / 7 | 1000 |
| 29 / 7 | 1318 | 29 / 7 | 1730 |
| 29 / 7 | 2015 | 29 / 7 | 2045 |
| 30 / 7 | 0145 | 30 / 7 | 1400 |
| 31 / 7 | 0620 | 31 / 7 | 0830 |
| 31 / 7 | 1133 | 31 / 7 | 1430 |
| Beginning Time | Ending Time | ||
|---|---|---|---|
| Day/Month | HKT | Day/Month | HKT |
| 8 / 7 | 1145 | 8 / 7 | 1745 |
| 9 / 7 | 0945 | 14 / 7 | 1830 |
| 15 / 7 | 1345 | 30 / 7 | 0945 |
| 31 / 7 | 0930 | 2 / 8 | 2025 |
| Meteorological Element | Figure of the Month | Departure from Normal* |
|---|---|---|
| Mean Daily Maximum Air Temperature | 33.3 degrees C | 1.7 degrees above normal |
| Mean Air Temperature | 30.3 degrees C | 1.4 degrees above normal |
| Mean Daily Minimum Air Temperature | 28.4 degrees C | 1.5 degrees above normal |
| Mean Dew Point Temperature | 25.6 degrees C | 0.4 degree above normal |
| Mean Relative Humidity | 77 % | 4 % below normal |
| Mean Cloud Amount | 61 % | 11 % below normal |
| Total Rainfall | 158.5 mm | 227.3 mm below normal |
| Number of hours of Reduced VisibilityΔ | 4 hours | 8.0 hours below normal§ |
| Total Bright Sunshine Duration | 226.2 hours | 28.9 hours above normal |
| Mean Daily Global Solar Radiation | 19.80 Megajoule / square metre | 2.58 Megajoule above normal |
| Total Evaporation | 126.4 mm | 15.6 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 |
| Record-breaking Events (since records began in 1884) |
Date / Period | New Record |
|---|---|---|
| Highest Number of Consecutive Hot Nights for July | 9 July to 29 July | 21 Days |
| Highest Number of Consecutive Hot Nights | 9 July to 29 July | 21 Days |
| Highest Daily Maximum Temperature for The Great Heat | 23 July 2022 | 34.9°C |
| Highest Temperature at Sheung Shui Weather Station (since records began in 2004) |
24 July 2022 | 39.0°C |
| Highest Maximum Temperature for July | 24 July 2022 | 36.1°C |
| Highest Daily Mean Temperature for July | 24 & 25 July 2022 | 32.0°C |
| Highest Daily Minimum Temperature for July | 25 July 2022 | 29.9°C |
| Highest Mean Maximum Temperature for July (on par with July 2020) |
July 2022 | 33.3°C |
| Highest Mean Temperature for July | July 2022 | 30.3°C |
| Highest Mean Minimum Temperature for July | July 2022 | 28.4°C |
| Highest Mean Maximum Temperature for All Months (on par with July 2020) |
July 2022 | 33.3°C |
| Highest Mean Temperature for All Months | July 2022 | 30.3°C |
| Highest Mean Minimum Temperature for All Months | July 2022 | 28.4°C |
| Highest Number of Days with Daily Maximum Temperature equal to or higher than 35.0°C for July |
July 2022 | 10 Days |
| Highest Number of Days with Daily Maximum Temperature equal to or higher than 35.0°C for All Months |
July 2022 | 10 Days |
| Highest Number of Hot Nights for July | July 2022 | 25 Days |
| Highest Number of Hot Nights for All Months | July 2022 | 25 Days |
| Highest Number of Very Hot Days for July | July 2022 | 21 Days |
| Highest Number of Very Hot Days for All Months | July 2022 | 21 Days |
| Highest Annual Number of Days with Daily Maximum Temperature equal to or higher than 35.0°C (Up to 31 July 2022) |
2022 | 10 Days |
| 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 |
