Oscar Romero has not yet been beatified so does not have a feast day.
Oscar Romero was shot while saying Mass on March 24, 1980.
March 30, 1980
Which Archbishop is being referred to cannot comment until a specific date is quoted
July 26 is the feast of St. Anne.
December 26 is the feast of Stephen.
Boston Blackie - 1951 A Date with Romero 2-26 was released on: USA: 10 April 1953
The feast of John the Baptist is June 24.
April 16 is the feast of St. Bernadette.
October 7 is the feast of Our Lady of the Most Holy Rosary.
The feast of St. Nicholas is on December 6.
Sometimes the feast day is the memorial of the date when the person died, or was reborn into Heaven. Sometimes it is another important date in the life of the person, such as the feast day of John Neumann which is the anniversary of the date he converted to Catholicism. Other times it is a date picked, more or less, in random.
May 1st is the feast of St. Joseph the Worker. He also has a feast day on March 19.