ENG-1989 — Page 378

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THE ENVIRON

ON June 5, World Environment Day, the government published a White Paper, Pollution in Hong Kong - A Time to Act, setting out its plans to combat pollution and achieve a more wholesome environment.

This chapter begins with a description of the natural environment and some of the environmental problems that face us, and then highlights the progress that took place last year in tackling these problems. An account of related services such as the meteorologi- cal, geophysical and oceanographic services provided by the government completes the chapter. -

Climate

Hong Kong's climate is sub-tropical, tending towards temperate for nearly half the year. During November and December there are pleasant breezes, plenty of sunshine and comfortable temperatures. Many people regard these as the best months of the year. January and February have rather more cloud, with occasional cold fronts followed by dry northerly winds. It is not uncommon for temperatures to drop below 10°C in urban areas. The lowest temperature recorded at the Royal Observatory is 0°C, although sub-zero temperatures and ice occur at times on high ground and in the New Territories.

March and April can also be very pleasant except for occasional spells of high humidity. Fog and drizzle can be particularly troublesome on high ground exposed to the south east, and air traffic and ferry services are occasionally disrupted by reduced visibility.

May to August are hot and humid with frequent showers and thunderstorms, par- ticularly during the mornings. Afternoon temperatures often exceed 32°C whereas at night, temperatures generally remain around 26°C with high humidity. There is usually a fine dry spell in July which may last for one to two weeks, or even longer in some years.

September is the month during which Hong Kong is most likely to be affected by tropical cyclones, although gales are not unusual at any time between May and November. On average, about 30 tropical cyclones form in the western North Pacific or China Seas every year, and about half of them reach typhoon strength (maximum winds of 118 kilometres per hour or more).

When a tropical cyclone is about 700 to 1 000 kilometres south east of Hong Kong, the weather is usually fine and exceptionally hot, but isolated thunderstorms sometimes occur in the evenings. If the centre moves closer to Hong Kong, winds increase and rain can become heavy and widespread. Heavy rain from tropical cyclones may last for a few days and subsequent landslips and flooding sometimes cause more damage than the winds.

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