The Weather of July 2002

    The weather of July 2002 was cloudier than usual, with a mean cloud amount of 79 percent which was 14 percent higher than normal. The total bright sunshine duration of 165.5 hours was 28 percent below normal. Although the month's total rainfall of 320.8 millimetres was only 2.7 millimetres less than normal, the accumulated rainfall since 1 January was 1114.7 millimetres, 15 percent below the normal for the same period.

    With an area of low pressure lingering over Beibu Wan, it was showery in the first four days of the month.   The weather improved on 5 July with plenty of sunshine and the temperature rose to 33.6 degrees, the highest recorded so far this year.

    A trough of low pressure formed over the northern part of the South China Sea on 6 July and brought showers and cloudier conditions to Hong Kong in the next couple of days.   The trough evolved into an area of low pressure later on 7 July.   The low pressure area intensified into a tropical depression on 8 July and then drifted northeast towards the Taiwan Strait.   Locally, the weather became hazy for the next two days under light wind conditions, with visibility falling to about 4000 metres in some places.

    Sunny and hot weather returned on 11 July and lasted for five days with maximum temperatures in the region of 33 degrees.   The southwest monsoon then set in necessitating the issuance of the Strong Monsoon Signal on 16 July.   The weather also deteriorated with heavy showers and isolated thunderstorms on 16 and 17 July.   Following the abatement of the southwest monsoon on 18 July, the weather became mainly fine apart from some showers for a week.

    The approach of a trough of low pressure from the north gave rise to showery weather again on 25 July which lasted till the end of the month.  The heavy showers on 29 July required the issuance of the Amber Rainstorm Warning, and more than 70 millimetres of rainfall was recorded in Kowloon and parts of the Hong Kong island on that day.

    A total of 8 tropical cyclones occurred in the western North Pacific and the South China Sea  in the month.

    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 July are tabulated in Table 2.