From the fifth network:

"The CW Network\'s hit drama One Tree Hill returns for Season 5 with a special two-hour
premiere on Tuesday, January 8, at 8 pm/ET. Subsequent episodes will take over the 9
pm time slot beginning Tuesday, Jan. 15, following an encore presentation of Crowned:
The Mother of All Pageants. Reaper will return to the schedule with original episodes later
in the season.

"The fifth season of One Tree Hill will be unprecedented in the annals of television drama,
as the show leaps forward four years. Season 4 ended as the young characters
graduated high school, and Season 5 begins, post-college, four years later."

Source: TVGuide.com