The Weather of December 1998

    December 1998 was much warmer than normal with the winter monsoon weak but dominating most of the month. The mean temperature of 19.1 degrees and the mean minimum temperature of 17.4 degrees were the sixth and the third highest respectively on record for the month. The total rainfall in the month was 13.7 millimetres, only about half of the normal amount.

    December started misty with light rain patches. Visibility was down to 1200 metres in the harbour on 1 December. However it became sunny the next day. A cold front crossed the coast of south China early on 3 December bringing some rain and brief spells of strong northerly winds offshore. Winds moderated the next day and generally cloudy and cooler weather remained till 6 December.

    Under the influence of a drier airstream from the north, it became fine on 7 December. Sunny weather prevailed during the next few days. Northerly winds strengthened on the morning of 11 December and moderated later during the day. Cloudy weather returned with periods of light rain on 13 December.

    Winds strengthened from the north again on 14 December bringing along cooler air and light rain patches. Temperatures dropped to 13.8 degrees that afternoon, the lowest in the month. Winds moderated the next day. Apart from an interlude of sunny weather on 17 December, it remained generally cloudy with rain the next few days. Rain was also heavy on 19 December in the western part of the New Territories.

    Fine and sunny weather returned on 21 December. Mist was reported over the western part of Hong Kong and temperatures at the Observatory rose to 25.7 degrees, the highest in the month, on the winter solstice on 22 December. As dry conditions developed, a hill fire occurred in Tseung Kwan O destroying about 400 000 square metres of trees on 23 December. Fine weather prevailed till the end of the month apart from periods of haze over the western areas from 27 to 29 December. Easterly winds strengthened briefly offshore early on 30 December.

    Two tropical cyclones formed in the western North Pacific and the South China Sea in the month.

    During the month, no aircraft was diverted due to adverse weather.