Red sky at morning ...

[williamtl]

I’ve always heard the phrase “red sky at morning sailor take warning, red sky at night, sailor’s delight”

This seems to be true, but I can’t figure out why. Logically it seems to me it would be true in some parts of the world but not others.

Can anyone shed any light on this old saying?

 

[PotomacDaysailer]

From https://en.wikipedia.org/wiki/Red_sky_at_morning:
"[...] It is based on the reddish glow of the morning or evening sky, caused by haze or clouds related to storms in the region.[2][3][5] If the morning skies are red, it is because clear skies over the horizon to the east permit the sun to light the undersides of moisture-bearing clouds. The saying assumes that more such clouds are coming in from the west. Conversely, in order to see red clouds in the evening, sunlight must have a clear path from the west, so therefore the prevailing westerly wind must be bringing clear skies.
[...]
Because of different prevailing wind patterns around the globe, the traditional rhyme is generally not correct at lower latitudes of both hemispheres, where prevailing winds are from east to west. The rhyme is generally correct at mid-latitudes where, due to the rotation of the Earth, prevailing winds travel west to east."
So, yeah, it is more true some places than others, but more people live and/or navigate where it's more often true.

 

[justsomeguy]

Somebody's got the interwebs.

 

[David in Sandusky]

My understanding is that this saying applies in the east winds of the trades. The red skies indicate weather. If you see them in the morning, weather is coming at you, at night weather is going away, and all is well.

 

[Indysailor]

What David says. Weather tends to come from the west, so sun rising in the east reflects against a front moving in from the west...and portends heavy weather. The opposite is true at sunset, as the sun reflects on heavy weather clearing out to the east.