Hong Kong is located on China's south coast, 60 km (37 mi) 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 Sham Chun River. The territory's 2,755 km2 (1,064 sq mi) area 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, 1,106 km2 (427 sq mi) is land and 1,649 km2 (637 sq mi) is water. Hong Kong claims territorial waters to a distance of 3 nautical miles (5.6 km). Its land area makes Hong Kong the 167th largest inhabited territory in the world. Less than 25% of Hong Kong's land area is built-up, while the majority is grassland, woodland, shrubland, and agricultural land.
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. Low altitude vegetation in Hong Kong is dominated by secondary rainforests, as the primary forest was mostly cleared during the Second World War, and higher altitudes are dominated by grasslands. 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, 957 metres (3,140 ft) above sea level. Hong Kong's long and irregular coast provides it with many bays, rivers and beaches. On 18 September 2011, UNESCO listed the Hong Kong National Geopark as part of its Global Geoparks Network. Hong Kong Geopark is made up of eight Geo-Areas distributed across the Sai Kung Volcanic Rock Region and Northeast New Territories Sedimentary Rock Region.
Despite Hong Kong's reputation of being intensely urbanised, the territory has tried to promote a green environment, and recent growing public concern has prompted the severe restriction of further land reclamation from Victoria Harbour. 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.
Though it is situated just south of the Tropic of Cancer, Hong Kong has a humid subtropical climate (Köppen Cwa). Summer is hot and humid with occasional showers and thunderstorms, and warm air coming from the southwest. Typhoons most often occur in summer. They sometimes result in flooding or landslides. Winters are mild and usually start sunny, becoming cloudier towards February; the occasional cold front brings strong, cooling winds from the north. The most temperate seasons are spring, which can be changeable, and autumn, which is generally sunny and dry. Snowfall is extremely rare, and usually occurs in areas of high elevation. Hong Kong averages 1,948 hours of sunshine per year, while the highest and lowest ever recorded temperatures at the Hong Kong Observatory are 36.3 °C (97.3 °F) on 8 August 2015 and 0.0 °C (32.0 °F) on 18 January 1893, respectively. The highest and lowest ever recorded temperatures across all of Hong Kong, on the other hand, are 37.9 °C (100.2 °F) at Happy Valley on 8 August 2015 and −6.0 °C (21.2 °F) at Tai Mo Shan on 24 January 2016, respectively. With data beginning in 1998, the highest and lowest temperatures ever recorded at the Hong Kong International Airport are 37.7 °C (99.9 °F) on 9 August 2015 and 2.9 °C (37.2 °F) on 24 January 2016, respectively.