Red Sky at night, Sailor's delight;
Red Sky in morning, Sailor take warning.
I love this timeless, classic idiom! It's simply a phrase by which people can relate to, as it concerns prediction of weather... meaning that if you see a gorgeous red sky at night, then it's a strong sign that good weather will follow the next day. Shakespeare once referred to it in the play,
Venus and Adonis, as well.
This Sailor's proverb is mostly true, but to learn about other interesting ideas associated with this idiom, here's a great link to discover more:
https://www.loc.gov/rr/scitech/myste...er-sailor.html