Beijing has a monsoon-influenced humid continental climate (Köppen climate classification Dwa), characterised by higher humidity in the summers due to the East Asian monsoon, and colder, windier, drier winters that reflect the influence of the vast Siberian anticyclone. Spring can bear witness to sandstorms blowing in from theGobi Desert across the Mongolian steppe, accompanied by rapidly warming, but generally dry, conditions. Autumn, like spring, is a season of transition and minimal precipitation. The monthly daily average temperature in January is −3.7 °C (25.3 °F), while in July it is 26.2 °C (79.2 °F). Precipitation averages around 570 mm (22 in) annually, with close to three-fourths of that total falling from June to August. With monthly percent possible sunshine ranging from 47% in July to 65% in January and February, the city receives 2,671 hours of bright sunshine annually. Extremes since 1951 have ranged from −27.4 °C (−17.3 °F) on 22 February 1966 to 41.9 °C (107.4 °F) on 24 July 1999 (unofficial record of 42.6 °C (108.7 °F) was set on 15 June 1942).
Beijing is situated at the northern tip of the roughly triangular North China Plain, which opens to the south and east of the city. Mountains to the north, northwest and west shield the city and northern China's agricultural heartland from the encroaching desert steppes. The northwestern part of the municipality, especially Yanqing County and Huairou District, are dominated by the Jundu Mountains, while the western part is framed by Xishan or the Western Hills. TheGreat Wall of China across the northern part of Beijing Municipality was built on the rugged topography to defend against nomadic incursions from the steppes. Mount Dongling, in the Western Hills and on the border with Hebei, is the municipality's highest point, with an altitude of 2,303 metres (7,556 ft).
Major rivers flowing through the municipality, including the Chaobai, Yongding, Juma, are all tributaries in the Hai River system, and flow in a southeasterly direction. The Miyun Reservoir, on the upper reaches of the Chaobai River, is the largest reservoir within the municipality. Beijing is also the northern terminus of the Grand Canal to Hangzhou,which was built over 1,400 years ago as a transportation route, and the South–North Water Transfer Project, constructed in the past decade to bring water from the Yangtze River basin.
The urban area of Beijing, on the plains in the south-central of the municipality with elevation of 40 to 60 metres (130–200 feet), occupies a relatively small but expanding portion of the municipality's area. The city spreads out in concentric ring roads. The Second Ring Road traces the old city walls and the Sixth Ring Roadconnects satellite towns in the surrounding suburbs. Tian'anmen and Tian'anmen Square are at the centre of Beijing, directly to the south of the Forbidden City, the former residence of the emperors of China. To the west of Tian'anmen is Zhongnanhai, the residence of China's current leaders. Chang'an Avenue, which cuts between Tiananmen and the Square, forms the city's main east-west axis.