The climate of Chongqing is semi-tropical, with the two-season monsoonal variations typical of South Asia. It has hot summers, and the temperature can be as high as 40 C (102F). It is known as one of the "three furnaces" of China, the other two being Wuhan and Nanjing. In the winter, it is wet and warm. While it seldom snows, most days are foggy.

The typically severe fogs were protective during World War II as the city was periodically bombarded by japanese aircraft - their aircrew were unable to effectively target their bombs using optical bombsights. The prevalent black tile roofs of buildings would also tend to blend into the ground colors and so became an effective form of camouflage.

As is true of most of China, the city often experiences severe air pollution, largely as a result of the burning of coal without pollution controls. Coal is burned both for industrial processess and for the production of electric power. Also, due to the surrounding mountains, a lack of wind makes the air pollution in the city even worse.