Red Sky at Night Sailors’ Delight

When I was a kid my father told me of an old saying about the color of the sky in the morning or evening; red sky in the morning, sailors’ take warning, red sky at night, sailors’ delight. According to WikipediA, the saying’s is more than old, it’s ancient with the concept of using the color of the sky to predict weather referenced in the New Testament: 2 He answered them, “When it is evening, you say, ‘It will be fair weather, for the sky is red.’ 3 And in the morning, ‘It will be stormy today, for the sky is red and threatening.’ You know how to interpret the appearance of the sky, but you cannot interpret the signs of the times.¹ (Matthew 16:2-3).

The rhyme is a rule of thumb used for weather forecasting during the past two thousand years. It is based on the reddish glow of the morning or evening sky, caused by haze or clouds related to storms in the region. 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.

There are occasions where a storm system might rain itself out before reaching the observer (who had seen the morning red sky). For ships at sea however, the wind and rough seas from an approaching storm system could still be a problem, even without rainfall.²

According to ScienceDaily, colors in a sunset are caused by a phenomenon called scattering where molecules and particles in the atmosphere cause light to change direction and scatter affecting the color in the sky, but the details are determined by the wavelength of the light and the size of the particle.³

“Because the sun is low on the horizon, sunlight passes through more air at sunset and sunrise than during the day, when the sun is higher in the sky. More atmosphere means more molecules to scatter the violet and blue light away from your eyes. If the path is long enough, all of the blue and violet light scatters out of your line of sight. The other colors continue on their way to your eyes. This is why sunsets are often yellow, orange, and red.” says Steven Ackerman, professor of meteorology at UW-Madison.

So there you have it, a prime example of lore, in this case ancient, being passed down through the generations.

Picture provided by Toni Brown

¹www.biblegateway.com
²www.wikipedia.com
³www.sciencedaily.com

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