Reality Shows has this info via way of the Big Brother 15 Blog.
It looks like we have our first news of the upcoming 15th season of Big Brother on CBS. Apparently, CBS has been impressed with the Summer ratings of Big Brother and ordered up an extension-resulting in a longer season in Summer 2013.
Check out the Big Brother 15 Extended Season News from the Reality Shows Blog:
"Well, out friends over at the Big Brother Blog have the news that the 15th season of popular reality show Big Brother will get an extended look from CBS brass next Summer.
Big Brother has been a perennial Summer ratings performer for CBS and one year even managed to run 2 seasons during the last writer's strike. While some fans have wanted Big Brother to come back for multiple seasons in one year, that option does not seem to be in the cards. However, fans will probably be excited about a couple more weeks of Big Brother 15 in the Summer of 2013:
that right, Big Brother 15 already has a premiere date and it comes
around 2 weeks earlier than the usual Big Brother time frame! That
means we are going to get at least a couple more weeks of Big Brother
action than normal ...
Along with the earlier start date comes a slightly different schedule as
the show will air on Sundays, Tuesdays, and the live eviction night
will be Wednesdays.
Be sure to mark your calendars now, June 26 and Big Brother 15 will be here before we know it!'
Can't wait for the start of Big Brother 15! Check back soon.