It was a Friday.
12 January 1979 was a Friday.
January 12, 1979, was a Friday.
January 12, 1979 was a Friday.
By googling it and finding which day of the week it was
January 1 1979 was on a Monday.
January 9 1979 was a Tuesday.
January 27, 1979 fell on a Saturday.
January 7, 1979 was a Sunday.
January 10, 1979 fell on a Wednesday.
January 29, 1979 fell on a Monday.
January 5th, 1979 fell on a Friday.
January 25, 1979 fell on a Thursday.