"Red sky morning, sailors take warning!" ?

[dhanson928]

Anybody want to explain why this old saying is usually pretty accurate?

[isobars]

It has to do with the location and timing of storms relative to the observer and whether they are moving towards or away from him. Google provides many more details than I'm willing to type and incredible photographs to boot.

[rigitrite]

First off, it's northern hemisphere biased. Weather in the southern hemisphere comes from the opposite direction. Anyway, it has to do with the angle of incidence between the rotating earth and the sun. In the evening, the suns rays illuminate a departing storms clouds (red sky at night, sailors delight). In the morning, the suns rays illuminate an approaching storms clouds (red sky in morning, sailors take warning). In the northern hemisphere, storms follow the jet stream, which flows west to east, so it works out.

[isobars]

It applies to the midlatitudes of both southern and northern hemispheres. It's near the equator that it fails.