Pittsburgh is a city of about 350,000 in Allegheny County, at the center of the Pittsburgh Region in southwestern Pennsylvania; the population of its metropolitan area is about 2.4 million. It is situated at the confluence of the Monongahela and Allegheny Rivers, which meet to form the Ohio River. Pittsburgh's triangular shape and steep hills have resulted in an unusual city design, a hodge-podge of neighborhood "pockets" with diverse ethnic and architectural heritage. Pittsburgh has a humid subtropical climate (Cfa) on the Koppen climate classification. This climate is quite diverse, and Pittsburgh features a colder and longer winter than Orlando, which is also in this climate zone. Therefore, Pittsburgh's climate can be thought of as a hybrid between humid subtropical (Cfa) and humid continental (Dfa). The city's climate features abundant precipitation throughout the year and four defined seasons. While there are wide variations in seasonal temperature common to temperate climates, winters are somewhat moderated by both proximity to the Atlantic Ocean and mountains that block the advance of cold air from the north. However, Pittsburgh's average winter temperatures are notably lower than that of Philadelphia. Overall, the city's climate features cold winters with snow, and warm, humid summers with frequent clouds and precipitation. The warmest month of the year in Pittsburgh, as in most of the northern hemisphere, is July. The average high temperature is 83 °F (28 °C), with overnight low temperatures averaging 62 °F (17 °C). July is often humid, resulting in a considerable heat index. The coldest month of the year is January, when the average high temperature is 37 °F (3 °C). Overnight low temperatures average 20 °F (-7 °C). The moderating influence of Pittsburgh's proximity to the Atlantic Ocean is evident in the fact that Chicago, which is less than 110 mi (177 km) north of Pittsburgh (and about 400 miles (640 km) west), experiences average January temperatures 7°F (4°C) colder on average. The highest temperature ever recorded in Pittsburgh was 101 °F (38 °C), on July 16, 1988, and the coldest temperature ever recorded was -19 °F (-28 °C), on January 19, 1994. http://wikitravel.org/en/Pittsburgh