Mainly attributing to the warmer than normal sea surface temperature and stronger than usual southerly flow in the lower atmosphere over the northern part of the South China Sea, April 2024 was much warmer than usual.  The monthly mean maximum temperature of 28.9 degrees, monthly mean temperature of 26.4 degrees and monthly mean minimum temperature of 24.5 degrees were 3.3 degrees, 3.4 degrees and 3.4 degrees above their corresponding normals and all of them were the highest on record for April.  Affected by a number of troughs of low pressure, the month was also wetter than usual with a total rainfall of 257.1 millimetres, about 68 percent more than the normal figure of 153.0 millimetres.  The accumulated rainfall recorded in the first four months of the year was 289.5 millimetres, about 4 percent below the normal figure of 300.4 millimetres for the same period.

Under the influence of a fresh to strong easterly airstream, it was relatively cooler with a few light rain patches on 9 April.  With the band of clouds covering the coastal areas of Guangdong thinning out gradually, local weather became dry with sunny periods during the day on 10 April.  Affected by an anticyclone aloft and the subsequent southerly airstream, it was generally fine and hot during the day on 11 – 17 April.  With plenty of sunshine, the temperatures at the Observatory rose to a maximum of 31.9 degrees on the afternoon of 13 April, the highest of the month.  There was also coastal fog at first on 15 April.  Under the influence of a trough of low pressure, it was mainly cloudy with showers and squally thunderstorms on 18 April.  The showers were heavy at times and more than 30 millimetres of rainfall were recorded over the eastern part of the territory and parts of the New Territories.  A southerly airstream brought a few showers and isolated thunderstorms to Hong Kong on the next day. 

The trough of low pressure returned and lingered over the coast of Guangdong again on 25 – 28 April.  The weather of Hong Kong became unsettled with occasional showers and squally thunderstorms.  The showers were particularly heavy on 26 April.  More than 30 millimetres of rainfall were generally recorded over the territory and rainfall even exceeded 100 millimetres over Sai Kung and Sha Tin Districts on that day.  Besides, the daily mean temperature of 28.8 degrees and daily minimum temperature of 27.7 degrees on 27 April were both the highest on record for April.  Under the influence of a southerly airstream, local weather was hot with sunny intervals during the day on 29 April.  While there were sunny intervals during the day on the last day of the month, affected by an area of intense thundery showers associated with a trough of low pressure, the weather deteriorated with outbreaks of heavy showers and severe squally thunderstorms that night.  About 30 millimetres of rainfall were recorded over many places of the territory.  Hail was reported at Yuen Long.  Violent gusts of around 110 kilometres per hour were once recorded at Tai O.  A taxi in Aberdeen was damaged by a fallen tree.

There was no tropical cyclone over the South China Sea and the western North Pacific in April 2024.

Details of issuance and cancellation of various warnings/signals in the month are summarised in Tables 1.1 to 1.4.  Monthly meteorological figures and departures from normal for April are tabulated in Table 2.