August 13, 1959, was a Thursday.
Thursday
It was a Thursday.
April, 13th, 1959, was a Monday.
August 13, 1990 was a Monday.
August 13 1999 was a Friday.
August 13, 1960 fell on a Saturday.
August 13, 1963 fell on a Tuesday.
13th, August, 1966, was a Saturday.
August 13, 1976 was most certainly a Friday. (Boo!)
It was a Friday.
Saturday
This varies from year to year. The 13th, August, 2010, is a Friday.