Considering that GG has always premiered sometime in September, that seems to lend ample time to many an episode, right? Not so fast. Pedowitz says The CW is holding their premieres until early October to give them more “traction,” saying, “We can run straight through October and November without any repeats.” So with Gossip Girl premiering on October 8, that means four Mondays in October and four Mondays in November. This should mean that Gossip Girl's final episode will air on Monday, December 10. Of course, that date is still subject to change a little based on scheduling.
In any case, GG will be over and done by the New Year. We’ll resolve to put on a brave face for 2013, but we’re not going to lie: It will be difficult. How totally strange is a world without Gossip Girl? Source: TVLine