The average Super Bowl kickoff time is 6:30 p.m. EST. Since the average Super Bowl lasts about 3 hours and 30 minutes with commercials included, this time is chosen so the game occurs during primetime hours in the Eastern time zone.
Since 1991, the kickoff of every Super Bowl has occurred between 6:20 p.m. and 6:40 p.m.. Before 1991, the Super Bowl's kickoff time fluctuated more. Super Bowl V in 1971 kicked off at 2 p.m., the earliest start of any Super Bowl. Once the Super Bowl started kicking off in the primetime hours consistently, viewership drastically increased year by year. In 2015, the Super Bowl had a record viewership of 114.4 million.