December 20, 1980 was on a Saturday.
20 January 1980 was a Sunday.
May 20 1980 was a Tuesday.
20 December 1957 was a Friday.
December 20, 1982 was a Monday.
December 20, 1955 was on a Tuesday.
December 20, 1990 was on a Thursday.
December 20, 2000 was on a Wednesday.
December 20, 2009 was on a Sunday.
December 20, 1953 was on a Sunday.
Friday
October 20th 1980 was a Monday.
December 20, 1966 fell on a Tuesday.