It may be time to break out your blues. The date of the semiannual uniform change over from whites to blues is set by each of the 12 Navy regions, but wide swaths of the U.S. are changing over now. Blues became the official dress uniform for sailors from Maine to Maryland on Monday, just in time for a cold snap hitting the east coast. Sailors in the Washington, D.C., area are also switching to blues. But sailors in North Carolina and Virginia will have to wait two more weeks, until the third Monday in October, to don their blues.…