Monday
March 21, 1966 was the 3rd Monday in March for that year.
July 21, 1966 fell on a Thursday.
It was a Tuesday.
It was a Wednesday.
December 21, 1966 was a Wednesday.
21 March 1960 was a Monday.
21 March 1950 was a Tuesday.
21 March 1959 was a Saturday.
March 21 1946 was a Thursday.
March 21 2005 was a Monday.
March 21 2010 was a Sunday.
March 21, 1948 was a Sunday.