Hong Kong is located on China's south coast, 60 km east of Macau on the opposite side of the Pearl River Delta. It is surrounded by the South China Sea on the east, south, and west, and borders the Guangdong city of Shenzhen to the north over the Shenzhen River. The territory's area of 1,104 square kilometers consists of Hong Kong Island, the Kowloon Peninsula, the New Territories, and over 200 offshore islands, of which the largest is Lantau Island. Of the total area, 1,054 square kilometers is land and 50 square kilometers is inland water. In addition Hong Kong claims territorial waters to a distance of 3 nautical miles (5.6 km). The land area makes Hong Kong the 179th largest habited territory in the world.
As much of Hong Kong's terrain is hilly to mountainous with steep slopes, less than 25% of the territory's landmass is developed, and about 40% of the remaining land area is reserved as country parks and nature reserves. Most of the territory's urban development exists on Kowloon peninsula, along the northern edge of Hong Kong Island and in scattered settlements throughout the New Territories. The highest elevation in the territory is at Tai Mo Shan, at a height of 957 meters (3,140 feet) above sea level. Hong Kong's long, irregular and curvaceous coast line provides it with many bays, rivers and beaches.
Despite Hong Kong's reputation of being intensely urbanised, the territory has made much effort to promote a green environment, and recent growing public concern has prompted the severe restriction of further land reclamation from Victoria Harbor. Awareness of the environment is growing as Hong Kong suffers from increasing pollution compounded by its geography and tall buildings. Approximately 80% of the city's smog originates from other parts of the Pearl River Delta.
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 are cloudier, with occasional cold fronts followed by dry northerly winds. It is not uncommon for temperatures to drop below 10℃ in urban areas. The lowest temperature recorded at the Observatory is 0℃, although sub-zero temperatures and frost occur at times on high ground and in the New Territories.
March and April can also be very pleasant although there are occasional spells of high humidity. Fog and drizzle can be particularly troublesome on high ground which is exposed to the southeast and air traffic and ferry services are occasionally disrupted because of reduced visibility.
May to August is hot and humid with occasional showers and thunderstorms, particularly during the mornings. Afternoon temperatures often exceed 31℃ whereas at night, temperatures generally remain around 26℃ with high humidity. There is usually a fine dry spell in July which may possibly last for one to two weeks, or for even longer in some years.
July to September is the months 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 31 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 kilometers per hour or more).
When a tropical cyclone is about 700 to 1000 kilometers southeast of Hong Kong, the weather is usually fine and exceptionally hot, but isolated thunderstorms sometimes occur in the evenings. If the centre comes closer to Hong Kong, winds will 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 considerably more damage than the winds.
The mean annual rainfall ranges from around 1300 millimeters at Waglan Island to more than 3000 millimeters in the vicinity of Tai Mo Shan. About 80 percent of the rain falls between May and September. The wettest month is August, when rain occurs about four days out of seven and the average monthly rainfall at the Observatory is 391.4 millimeters. The driest month is January, when the monthly average is only 23.4 millimeters and rain falls only about six days a month.
Severe weather phenomena that can affect Hong Kong include tropical cyclones, strong winter monsoon winds, and thunderstorms with associated squalls that are most frequent from April to September. Waterspouts and hailstorms occur infrequently, while snow and tornadoes are rare.
wikipedia.org, hko.gov.hk