September 11 is the 254th day of the year (255th in leap years) in the Gregorian calendar. There are 111 days remaining until the end of the year.
This date is slightly more likely to fall on a Tuesday, Friday or Sunday (58 in 400 years each) than on Wednesday or Thursday (57), and slightly less likely to occur on a Monday or Saturday (56).
Between the years AD 1900 and 2099, September 11 of the Gregorian calendar is the leap day of the Coptic and Ethiopian calendars. These leap days occur in the years immediately before those which are leap years in the Julian and Gregorian calendars. In all common years of the Coptic and Ethiopian calendars, September 11 is New Year’s Day.