In American and Canadian television, a mid-season replacement is a television series that premieres in the second half of the traditional television season, usually between January and May. Mid-season replacements usually take place after a show that was in the fall schedule was canceled or put on hiatus, outside factors such as an actor's family emergency or personal illness led to a delay in the program's debut, a program was purposefully scheduled for mid-season (for example, shows NBC airs on Sunday nights after the NFL season ends, as it only takes up the first half of the television season), or a program had a shortened season for some other reason which resulted in a time slot that needed filling. A few shows in American television history have been perennial mid-season replacements; American Idol, for example, from its second season onward, aired from January to May each year, to great ratings success.
