The fact that it's on Wikipedia doesn't mean it's a common phrase. You can see from your own link that it comes from an ancient rhyme. Also remember that some liberties are taken with the language for poetry as words are fitted into a rhythm and a rhyme with little regard for grammar.
The rhyme I know is "Red sky at night, shepherd's delight, red sky in the morning, shepherd's warning".
And the joke version: Red sky at night, shepherd's delight, red sky in the morning, the shed's on fire".