In the history of North American major professional sports league championships (which include the NFL, MLB, NBA, and NHL) a city/metropolitan area has been home to multiple championships in a season fifteen times, most recently in 2008-2009, when the Pittsburgh Penguins and Pittsburgh Steelers won their respective leagues, in February and June of 2009. Only Detroit has been host to more than two major league championship teams in a season, although in 2002 Los Angeles metropolitan area's Lakers and Angels won the NBA and MLB championships along with two other local teams of smaller leagues (the Sparks of the WNBA and the Galaxy of the MLS).
Super Bowls take place in the February after the NFL's regular season. The Super Bowl used to be in January. Therefore, Super Bowl I, which took place January 15, 1967 is officially the championship game for the 1966 season. In the calendar year 2009, Pittsburgh's Steelers and Penguins won their respective championships, but the Steelers' championship was for the NFL's 2008 regular season. However, before 1965, the NFL championship game was played in December of that calendar year. That being said, both of those seasons started in 2008 and ended in 2009. Therefore, Pittsburgh was in fact the most recent city to win multiple championships in the same season.
All four of Philadelphia's major professional sports teams either played in the championship, or won titles in their respective sports following the 1980 season: The 1980 Philadelphia Phillies won the World Series, the 1980 Philadelphia Eagles lost Super Bowl XV, the 1979-80 Philadelphia 76ers lost the NBA Finals, while the 1979-80 Philadelphia Flyers lost the Stanley Cup Finals.