The Weather of January 1998

    January 1998 was slightly warmer than normal. The maximum temperature in the month, 25.9 degrees, was the eighth highest for January and the mean temperature of 16.8 degrees was one degree higher than normal. On the other hand, the total bright sunshine duration of 86.0 hours was 66.4 hours below normal while the mean monthly total cloud amount of 77 per cent was 19 per cent higher than normal. The total rainfall in the month was 48.9 millimetres against a normal of 23.4 millimetres.

    The first day of 1998 was warm and sunny. A weak cold front crossed the south China coast in the evening and generally fine weather prevailed during the next few days. Another cold front crossed the coast on the afternoon of 4 January bringing cooler air to Hong Kong. Winds freshened from the north but moderated the next day. The weather became cloudy and there were light rain patches on the mornings of 7 and 8 January.

    A maritime airstream affected our region on 8 January and temperatures rose to 25.9 degrees that afternoon, the highest in the month. Easterly winds freshened on 9 January bringing periods of rain to local areas. Winds subsided the next day and there were mist patches in the harbour as rain eased off.

    It was sunny and warm on 11 January, but a cold front crossed the coastal areas that afternoon. Winds strengthened from the east the next day and it became cloudy with periods of light rain. Easterly winds moderated on 13 January. Another cold front crossed Hong Kong on 14 January accompanied by heavy and thundery showers in the afternoon and early the next day. The second half of the month saw cooler temperatures than the first couple of weeks.

    It became fine and sunny during the day on 15 January, but cloudy condition with periods of rain returned the following day. A dry northerly airstream reached Hong Kong on 17 January clearing up the clouds. Winds became strong offshore in the afternoon and persisted till next morning.

    Cloudy weather returned on 19 January. Widespread mist occurred on 20 January till the morning of 23 January. In particular, fog was reported at Chep Lap Kok on 22 January with visibility there reduced to 600 metres. Visibility improved significantly on 23 January after the passage of a cold front. Winds were strong at times offshore but the weather remained cloudy to overcast. Temperatures dropped to 9.7 degrees, the lowest in the month, on 24 January. Winds turned more to the east and moderated the next day while cloudy to overcast conditions persisted the next couple of days.

    There were long sunny periods on 28 January as a drier airstream behind a cold front reached the coastal areas. Although it was cloudy again on 29 January, the weather was fine and sunny the last two days of the month.

    During the month, no tropical cyclone occurred in the western North Pacific or the South China Sea. No aircraft was diverted due to adverse weather.