The Weather of December 2002

    December 2002 was cloudier and wetter than usual.  The total bright sunshine duration of 125.8 hours was about 30 per cent below normal.  The monthly rainfall was 64.1 millimetres, some 2.3 times the normal amount of 27.3 millimetres.  The annual rainfall for 2002 was 2490.0 millimetres, 12 per cent higher than the normal figure of 2214.3 millimetres.

    It was overcast with light rain in the first two days of December.  It became fine on 3 and 4 December.  As a moist easterly airstream set in on 5 December, it turned cloudy with light rain again.   Mist and fog were reported in three consecutive mornings.  The visibility at Waglan Island at times dropped to around 100 metres.  Clouds dispersed in the afternoon of 7 December and the temperature rose to a maximum of 25.7 degrees, the highest in the month.

    A cold front reached the South China coast on the small hours of 8 December and brought rain and windy conditions to Hong Kong.   The strong northerly winds blew down a temporary structure during a charity carnival in Sha Tin that day and slightly injured a person.  The temperature fell sharply by more than 10 degrees on that day.

    It remained cold with light rain on 9 December, but it turned fine rapidly the following day.  The fine weather was short-lived, however, as a rain-bearing cloud band swept across Hong Kong on 11 December.   With the cloud band passing to the east, the weather in Hong Kong became mainly fine in the next five days apart from a few light rain patches at night time.

    A moist airstream set in on 17 December and it became cloudy with morning mist the next two days.  On 19 December, thunderstorms associated with a cold front affected the New Territories and necessitated the issuance of Thunderstorm Warning, the first in December since the introduction of the Thunderstorm Warning System began in 1967.  The unsettled weather continued into the next day.  The weather improved on 21 December and it remained fine in the next four days.

    An intense surge of the winter monsoon arrived Hong Kong on 25 December.  Amidst continuous rain on 26 and 27 December, the temperature dropped to 6.8 degrees, the lowest so far this winter.  Twelve incidences of death were reported to be related to the cold weather.   Sunny periods in the next 3 days brought slightly warmer weather to Hong Kong.  On 30 December, it was hazy under light northerly winds.  It was cloudy with a few light rain patches in the last day of the year.

    Only one tropical cyclone occurred over the western North Pacific 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 December are tabulated in Table 2.