The Weather of March 2023
4 April 2023
With the northeast monsoon over southern China generally weaker than normal for most of the time in the month, March 2023 continued to be much warmer than usual in Hong Kong. The monthly mean temperature of 21.3 degrees, monthly mean minimum temperature of 19.4 degrees and monthly mean maximum temperature of 24.2 degrees were 1.8 degree, 1.8 degrees and 2.3 degrees above their corresponding normals and respectively one of the fourth, one of the fifth and the fifth highest on record for March. The total rainfall in the month was 70.3 millimetres, about 7 percent below the normal figure of 75.3 millimetres. The accumulated rainfall recorded in the first three months of the year was 90.1 millimetres, about 39 percent below the normal figure of 147.4 millimetres for the same period.
Under the influence of a dry northeast monsoon and the subsequent easterly airstream, the weather of Hong Kong was generally fine and dry on the first eleven days of the month. It was cool on the morning of 1 March with the temperatures at the Observatory falling to a minimum of 16.4 degrees, the lowest of the month. It was also very dry during the day on 5 – 6 March. With the moderation of the easterly airstream, there were sunny intervals and a few light rain patches during the day on 12 March. Under light wind conditions, the visibility over parts of the territory was relatively low at first on that day.
Meanwhile, a weak cold front moved across the coast of Guangdong on the evening of 12 March and brought slightly cooler and cloudier weather to Hong Kong in the next two days. There were also a few light rain patches at first on 13 March. With the moderate of the northeast monsoon, apart from a few light rain patches on the morning of 17 March, it was warm with sunny periods during the day in Hong Kong on 15 – 18 March. The visibility was also relatively low at first on 18 March.
With a band of clouds covering the coast of Guangdong, local weather turned mainly cloudy with a few rain patches on 19 – 21 March. Under the influence of a southerly airstream, the weather remained cloudy with a few showers on 22 – 23 March. With sunny periods during the day, it was hot on 24 March. The temperatures at the Observatory rose to a maximum of 29.0 degrees in that afternoon, the highest of the month.
Meanwhile, a trough of low pressure over inland Guangdong developed into a cold front and moved across the coast of Guangdong on the morning of 25 March. A band of intense thundery showers associated with the cold front affected Hong Kong on that day. More than 30 millimetres of rainfall were generally recorded over the territory and rainfall even exceeded 50 millimetres over parts of the urban areas and New Territories. Hail was also reported at the vicinity of Sai Wan Ho during the passage of the thunderstorms in that afternoon. Under the influence of a strong northeast monsoon and the subsequent upper-air disturbances, it was cooler and mainly cloudy with a few showers till the end of the month. There were also a few isolated thunderstorms on 27 March. The visibility was rather low over parts of the territory on 30 - 31 March.
There was no tropical cyclone over the South China Sea and the western North Pacific in March 2023.
Details of issuance and cancellation of various warnings/signals in the month are summarized in Tables 1.1 to 1.4. Monthly meteorological figures and departures from normal for March are tabulated in Table 2.
With the northeast monsoon over southern China generally weaker than normal for most of the time in the month, March 2023 continued to be much warmer than usual in Hong Kong. The monthly mean temperature of 21.3 degrees, monthly mean minimum temperature of 19.4 degrees and monthly mean maximum temperature of 24.2 degrees were 1.8 degree, 1.8 degrees and 2.3 degrees above their corresponding normals and respectively one of the fourth, one of the fifth and the fifth highest on record for March. The total rainfall in the month was 70.3 millimetres, about 7 percent below the normal figure of 75.3 millimetres. The accumulated rainfall recorded in the first three months of the year was 90.1 millimetres, about 39 percent below the normal figure of 147.4 millimetres for the same period.
Under the influence of a dry northeast monsoon and the subsequent easterly airstream, the weather of Hong Kong was generally fine and dry on the first eleven days of the month. It was cool on the morning of 1 March with the temperatures at the Observatory falling to a minimum of 16.4 degrees, the lowest of the month. It was also very dry during the day on 5 – 6 March. With the moderation of the easterly airstream, there were sunny intervals and a few light rain patches during the day on 12 March. Under light wind conditions, the visibility over parts of the territory was relatively low at first on that day.
Meanwhile, a weak cold front moved across the coast of Guangdong on the evening of 12 March and brought slightly cooler and cloudier weather to Hong Kong in the next two days. There were also a few light rain patches at first on 13 March. With the moderate of the northeast monsoon, apart from a few light rain patches on the morning of 17 March, it was warm with sunny periods during the day in Hong Kong on 15 – 18 March. The visibility was also relatively low at first on 18 March.
With a band of clouds covering the coast of Guangdong, local weather turned mainly cloudy with a few rain patches on 19 – 21 March. Under the influence of a southerly airstream, the weather remained cloudy with a few showers on 22 – 23 March. With sunny periods during the day, it was hot on 24 March. The temperatures at the Observatory rose to a maximum of 29.0 degrees in that afternoon, the highest of the month.
Meanwhile, a trough of low pressure over inland Guangdong developed into a cold front and moved across the coast of Guangdong on the morning of 25 March. A band of intense thundery showers associated with the cold front affected Hong Kong on that day. More than 30 millimetres of rainfall were generally recorded over the territory and rainfall even exceeded 50 millimetres over parts of the urban areas and New Territories. Hail was also reported at the vicinity of Sai Wan Ho during the passage of the thunderstorms in that afternoon. Under the influence of a strong northeast monsoon and the subsequent upper-air disturbances, it was cooler and mainly cloudy with a few showers till the end of the month. There were also a few isolated thunderstorms on 27 March. The visibility was rather low over parts of the territory on 30 - 31 March.
There was no tropical cyclone over the South China Sea and the western North Pacific in March 2023.
Details of issuance and cancellation of various warnings/signals in the month are summarized in Tables 1.1 to 1.4. Monthly meteorological figures and departures from normal for March are tabulated in Table 2.
Warnings and Signals issued in March 2023
| Beginning Time | Ending Time | ||
|---|---|---|---|
| Day/Month | HKT | Day/Month | HKT |
| 27 / 3 | 0520 | 28 / 3 | 0745 |
| Colour | Beginning Time | Ending Time | ||
|---|---|---|---|---|
| Day/Month | HKT | Day/Month | HKT | |
| Amber | 25 / 3 | 1220 | 25 / 3 | 1520 |
| Beginning Time | Ending Time | ||
|---|---|---|---|
| Day/Month | HKT | Day/Month | HKT |
| 25 / 3 | 1135 | 26 / 3 | 0440 |
| 26 / 3 | 0630 | 26 / 3 | 0900 |
| 27 / 3 | 0150 | 27 / 3 | 0545 |
| Colour | Beginning Time | Ending Time | ||
|---|---|---|---|---|
| Day/Month | HKT | Day/Month | HKT | |
| Red | 3 / 3 | 0600 | 4 / 3 | 0600 |
| Yellow | 4 / 3 | 0600 | 4 / 3 | 1145 |
| Red | 4 / 3 | 1145 | 4 / 3 | 2130 |
| Red | 5 / 3 | 0600 | 5 / 3 | 2315 |
| Red | 6 / 3 | 0600 | 6 / 3 | 2330 |
| Red | 7 / 3 | 0600 | 7 / 3 | 2145 |
| Yellow | 11 / 3 | 0600 | 11 / 3 | 1900 |
| Yellow | 12 / 3 | 1145 | 12 / 3 | 2330 |
| Yellow | 16 / 3 | 0600 | 16 / 3 | 2145 |
| Meteorological Element | Figure of the Month | Departure from Normal* |
|---|---|---|
| Mean Daily Maximum Air Temperature | 24.2 degrees C | 2.3 degrees above normal |
| Mean Air Temperature | 21.3 degrees C | 1.8 degrees above normal |
| Mean Daily Minimum Air Temperature | 19.4 degrees C | 1.8 degrees above normal |
| Mean Dew Point Temperature | 16.5 degrees C | 0.4 degree above normal |
| Mean Relative Humidity | 76 % | 6 % below normal |
| Mean Cloud Amount | 61 % | 16 % below normal |
| Total Rainfall | 70.3 mm | 5.0 mm below normal |
| Number of hours of Reduced VisibilityΔ | 9 hours | 85.8 hours below normal§ |
| Total Bright Sunshine Duration | 156.8 hours | 56.8 hours above normal |
| Mean Daily Global Solar Radiation | 13.13 Megajoule / square metre | 2.42 Megajoule above normal |
| Total Evaporation | 80.4 mm | 7.2 mm above 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 2022 |
| 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 |
