Yes, there's a common phrase about how the red sky at night means sailor's delight.
Yes, I believe it is- red sky at morning, sailor's take warning too.
The number of 7 is a really interesting number. Sounds interesting, do you know of the interesting number paradox? It's a sort of paradox which happens when natural numbers are classified as dull or interesting. No but I know people have superstitions of numbers, where did that even begin with? Much of those superstitions is actually based on sailing risks, luck, and omens and portents that are given associative meaning. Oh sailors, so like how a red sky has an associated meaning to it right?
The common phrase ''red sky at morning'' is a line from an ancient rhyme often repeated by mariners:  Red sky at night, sailors' delight.