The title of this episode comes from a rhyme used by sailors to predict the weather: "Red sky at morning, sailor's warning./Red sky at night, sailor's delight."
Sam refers to Ms. Case as "Lady Havisham" after the ball. This is in reference to Miss Havisham in the Charles Dickens novel "Great Expectations," who was a wealthy elderly woman that had never married after being left at the altar as a young woman by a man who defrauded her.
Sam says Happy Purim to Dean in the beginning of the episode. Purim is a Jewish holiday that commemorates the saving of the Jewish people from Haman, who was planning to kill all the Jews. This took place in the ancient Persian Empire.
Second time Bela uses an American, rather than English, accent (when interviewing the second victim's brother).
The name of the ghost ship is the "Espirito Santo", which is Portuguese for "Holy Spirit".