Sunday
Sept. 13, 1951 was on a Thursday.
Monday
It was a Sunday.
It was a Tuesday.
13 July 1970 was a Monday.
13 October 1970 was a Tuesday.
September 13, 1970 fell on a Sunday.
August 13, 1970 was a Thursday.
that was on a wednesday.
Friday
It was a Sunday.
That fell on a Friday.