The Weather of July 2000

    July 2000 was slightly drier than normal. The total rainfall of 304.0 millimetres was six per cent below normal. However, the accumulated rainfall since 1 January amounted to 1 642.1 millimetres, 25 per cent above the normal figure of 1 316.0 millimetres for the same period. Two tropical cyclones necessitated the hoisting of the Standby Signal No. 1. The Strong Monsoon Signal was also hoisted on two occasions. The Very Hot Weather Warning was in force for four episodes.

    Under the domination of the subtropical ridge of high pressure over the western Pacific, it was mainly fine and very hot on the first day of the month.

    Easterly winds affected the south China coastal areas the next few days.  Apart from periods of sunshine, there were a few showers and squally thunderstorms on 2 and 3 July.  Rain eased off on 4 July and it became very hot again under abundant sunshine.

    Meanwhile, Kai-tak developed as a tropical depression over the South China Sea west of Luzon.  It intensified into a typhoon and drifted slowly towards Taiwan during the next few days.  The weather in Hong Kong was hazy with scattered showers and squally thunderstorms in the afternoon and evening.  As Kai-tak moved further away, it became fine on 9 and 10 July apart from some showers.

    A ridge of high pressure over the Pacific and an area of low pressure near Hainan Island together brought strong southeasterly winds to the territory on 11 July.  The weather turned mainly cloudy with scattered showers.  Weather improved the next day as winds moderated.

    Under the influence of a ridge of high pressure over the Pacific, the weather was generally fine on 13 and 14 July apart from one or two isolated showers in the morning.

    An area of low pressure over the South China Sea near Xisha intensified into a tropical depression on 15 July.  Its outer rain bands began to affect Hong Kong in the afternoon, bringing squally showers and occasional strong winds to the offshore waters.  It made landfall over Hainan Island the next evening and dissipated quickly.

    Following the dissipation of the tropical depression, Hong Kong came under the influence of a strong and active southerly airstream on 17 July.  Weather deteriorated with heavy squally thunderstorms.  Winds subsided on 18 July but heavy rain and thunderstorms continued.  Temperatures dropped to a minimum of 24.5 degrees, the lowest in the month.  It remained cloudy with squally thunderstorms over the next three days.

    A ridge of high pressure over southeastern China brought generally fine weather to the territory on 22 July.  Sunny and very hot weather prevailed for the next few days.  With abundant sunshine, temperatures rose to a maximum of 33.2 degrees on 28 July, the highest in the month.

    A weak trough of low pressure along south China affected Hong Kong and brought scattered showers and thunderstorms on 31 July.

    Six tropical cyclones occurred in the South China Sea and the western North Pacific in the month.

    During the month, a total of 3 aircraft was diverted due to adverse weather.