Sony had a lot of success with James Bond in November that they decided to have a mega movie at that slot. Rory Bruer from Sony told that they have a lot of movies this coming summer.
This should give Roland Emmerich time to tweaks some effects.
Personally, I think it's a bad move by Sony. I see summer as the real season for big blockbuster movies where you leave your brain at the door. 2012 fall in that category. Autumn is for more "serious" story driven movie.
For example, Tom Hanks Road to Perdition was shown in the summer. It was a pretty good movie but was missing that Wow effect. It's not the same audience.
I'm sure that 2012 will make money but summer is a better fit this kind of movie.
I checked on IMDB and Sony don't have many other movies in July. I expect they will be forced to move one now.
Upcoming movies from Sony, Columbia, Screen Gems from May to August(Summer season):
Angels & Demons (15)
The Year One (19)
The Ugly Truth (24)
The Taking of Pelham 123 (28)
Julie & Julia (7)
District 9 (14)
Mardi Gras (28)
Like 2012, they could have other movies not set yet or moved.
Keywords: 2012, Entertainment, Movie, News, Amanda Peet, end of the world, John Cusack, Mayan, Roland Emmerich