Producer Don Murphy
over at his Message Boards
stated that Transformers 3 filming is scheduled to end in 6 weeks
According to News 13
... “Production crews and film stars will soon transform Brevard County and the Kennedy Space Center into a Hollywood Studio. Director Michael Bay will begin shooting portions of "Transformers 3" on the Space Coast in mid-to-late September. The Space Coast Film Commission told News 13 production specialists may begin arriving as early as next week to begin preparations.”
As for the Washington D.C Filming... "Kathy Hollinger, director of the D.C. Office of Motion Picture and Television Development, told POLITICO Thursday that the film is now set to begin shooting in town October 4th. The dates could change again, of course. But the crew has at least managed to nail down some filming locations, including the National Mall, near the monuments, outside the American Red Cross National Headquarters and outside DAR Constitution Hall, located just across from the Ellipse.
The National Park Service has made it difficult for Paramount Pictures to secure permission to film some scenes, including a race around the Mall. Hollinger said, however, that the studio is “still talking to the National Park Service to refine the requests to possibly get more flexibility.”" Very early reports
stated that, Transformers 3 filming might end on 1st of July, 2010.