The first season began and ended at midnight, and during its ninth episode (8:00 – 9:00 am) Jack mentioned that he had already been awake for 24 hours. In most subsequent seasons the story starts in the morning. Seasons two and seven began at 8:00 am, seasons four and five began at 7:00 am, and season six began at 6:00 am. This was a more realistic period of time for the characters to have been continuously awake. Season three began at 1:00 pm and season eight began at 4:00 pm.
The seventh season, originally scheduled to premiere on January 13, 2008, was postponed in the wake of the 2007–2008 Writers Guild of America strike. To ensure a nonstop season, a trademark of the show since the start of its fourth season in January 2005, the season was postponed a full year until January 2009. To help offset the strike-induced delay, the show returned on November 23, 2008, with a feature-length TV movie, 24: Redemption, that takes place nearly four years after season six and sets up the story that launched season seven.
Viewership increased midway through its second season when the mega-hit American Idol became the lead-in to 24 starting in February 2003. For its fourth season, Fox gave the show a vote of confidence by moving 24 out of the post-American Idol time slot (to make room for the eventual hit drama, House) and placed it on Monday nights at 9:00 pm Eastern while it aired the show in consecutive weeks, beginning in mid-January of 2005. The consecutive-week schedule was also implemented for 2006, beginning in mid-January 2006.
The sixth season's two-night, four-hour premiere, broadcast in 2007, garnered the largest audience in 24's history, averaging 15.7 million viewers. Ratings peaked at one point to 16.3 million. By comparison, the precedent seventh season's two-night, four-hour premiere, broadcast in 2009, decreased slightly in viewers, averaging an overall 27 million viewers over the two nights.