Pittsburgh, city in western Pennsylvania and seat of Allegheny County. Pittsburgh was the nation's foremost industrial city of the 19th century and was famous for its steel production. Beginning in the 1970s it underwent severe deindustrialization as its massive steel complexes began to close. Today Pittsburgh is a postindustrial city, with an economy based on services, especially medical, financial, corporate, and educational, rather than steel.
Pittsburgh sits astride the Monongahela and Allegheny rivers where they unite to form the Ohio River. Much of the city lies on hills surrounding this historic river junction, although Pittsburgh's downtown core is clustered on a wedge of level ground framed by the rivers and dubbed the “Golden Triangle.” Winters in Pittsburgh can be cold and snowy and summers hot and humid, but seasons are usually moderate. The average high temperature in January is 1°C (34°F) and the average low is -8°C (19°F); the average high in July is 28°C (83°F) and the average low is 16°C (62°F). The city annually receives 936 mm (36.9 in) of precipitation, with accumulations evenly distributed throughout the year.
