Located just south of the Tropic of Cancer, Guangzhou has a humid subtropical climate (Köppen Cfa) influenced by the East Asian monsoon. Summers are wet with high temperatures, high humidity, and a high heat index. Winters are mild and comparatively dry. Guangzhou has a lengthy monsoon season, spanning from April through September. Monthly averages range from 13.6 °C (56.5 °F) in January to 28.6 °C (83.5 °F) in July, while the annual mean is 22.6 °C (72.7 °F). Autumn, from October to December, is very moderate, cool and windy, and is the best travel time. The relative humidity is approximately 68 percent, whereas annual rainfall in the metropolitan area is over 1,700 mm (67 in). With monthly percent possible sunshine ranging from 17 percent in March and April to 52 percent in November, the city receives 1,628 hours of bright sunshine annually, considerably less than nearby Shenzhen and Hong Kong. Extreme temperatures have ranged from 0 °C (32 °F) to 39.1 °C (102.4 °F). The last recorded snowfall in the city was on 24 January 2016, 87 years after the second last recorded snowfall.
The old town of Guangzhou was near Baiyun Mountain on the east bank of the Pearl River (Zhujiang) about 80 miles (129 km) from its junction with the South China Sea and about 300 miles (483 km) below its head of navigation. It commanded the rich alluvial plain of the Pearl River Delta, with its connection to the sea protected at the Humen Strait. The present city spans 7,434.4 square kilometres (2,870.4 sq mi) on both sides of the river from 112° 57′ to 114° 03′ E longitude and 22° 26′ to 23° 56′ N latitude in south-central Guangdong. The Pearl is the 3rd-largest river of China. Baiyun Mountain is now locally referred to as the city’s “lung” (市肺).
The elevation of the prefecture generally increases from southwest to northeast, with mountains forming the backbone of the city and the ocean comprising the front. Tiantang Peak (天堂顶, “Heavenly Peak”) is the highest point of elevation at 1,210 metres (3,970 ft) above sea level.
There are 47 different types of minerals and also 820 ore fields in Guangzhou, including 18 large and medium-sized oil deposits. The major minerals are granite, cement limestone, ceramic clay, potassium, albite, salt mine, mirabilite, nepheline, syenite, fluorite, marble, mineral water, and geothermal mineral water. Since Guangzhou is located in the water-rich area of southern China, it has a wide water area with lots of rivers and water systems, accounting for 10% of the total land area. The rivers and streams improve the landscape and keep the ecological environment of the city stable.