Climate

Seoul's climate is characterized by a large annual range of temperature. The coldest bmonth, January, has a mean temperature of 26 F (-3 C), and the warmest month, August, has a mean temperature of 78 F (25 C). Yearly precipitation in the city is about 54 inches (1,370 millimetres), with a heavy concentration during the summer months. Air pollution in the basin and in Yongdung-p'o, an industrial area, has become a serious problem, caused in large part by the increasing number of automobiles and factories. For years the Han-gang was highly polluted, but since the early 1980s pollution levels have been reduced significantly by measures to control the river's water level and by the construction of large-scale sewage treatment facilities.