Explaining “Red sky at morning, sailors take warning; red sky at night, sailors’ delight.”

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Dear Tom,
Please explain the derivation of the phrase: “Red sky at morning, sailors take warning; red sky at night, sailors’ delight.” I’m curious about its meteorological explanation.
— Donald Worden
Dear Donald,
It’s been a while since we have addressed this frequently asked question. Variations of this adage can be traced back to biblical times and are based on the experiences of mariners who sailed the Earth’s middle latitudes, where storms generally travel from west to east.
The sky appears red when the setting or rising sun illuminates the underside of clouds. A red sunset often means that there are clouds in the east and clear skies to the west, an indication of approaching high pressure and good weather.
Red skies in the morning can mean clouds invading from the west, often the forerunner of approaching storms.

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