According to the Gregorian Calendar (The one America uses), it was a Friday.
20 October 1946 was a Sunday.
May 20 1946 was on a Monday.
November 20 1946 was a Wednesday.
20th June 1946, was a Thursday.
Friday
Wednesday
Saturday
Friday
August 20th, 1946 fell on a Tuesday.
December 20th, 1964 fell on a Sunday.
December 29th, 1959 fell on a Sunday. The following year, it fell on a Tuesday.
It was a Saturday.