My Grandpa Robb was quite the character, one of those Dust Bowl survivors who picked up and moved with Grandma to southern California from Missouri in the 1930s when there was no work to be had. He had no formal education to speak of, but the World War I veteran had a lot of street smarts. 

He was also the best fisherman I’ve ever been around and, together with my dad, they took me stream fishing for trout. And later, after dad bought a small boat, bass fishing in lakes and inshore saltwater fishing for salmon and halibut. During those fishing trips he and dad would banter on about the world, while I discovered early on that — if I kept my mouth shut and paid attention — I just might learn a few things. 

Grandpa was the first person I ever heard say, “Red sky at night, sailor’s delight. Red sky in morning, sailor take warning.” It was a day that started out with a gorgeous red sunrise on the ocean that made me think we were in for a long day of great fun that turned into one of those “batten down the hatches” days when the winds kicked up seemingly out of nowhere and we had to run for the marina like scalded dogs.

I didn’t think much about it then, being in grade school. But later, when I spent a lot of time guiding fishermen and hunters from a relatively small boat in in the oceans of southeast Alaska, it was a saying I took to heart. 

Being the curious sort, I researched it a bit. 

Was there really something concrete to this old adage that could help predict the weather, and thus, help us stay safe in places where Mother Nature can violently turn on you in a heartbeat?

Even Jesus noticed this phenomenon. In Matthew XVI: 2-3, Jesus said, “When in evening, ye say, it will be fair weather: For the sky is red. And in the morning, it will be foul weather today; for the sky is red and lowering.” And so did The Bard, William Shakespeare, who wrote in his play Venus and Adonis: “Like a red morn that ever yet betokened, Wreck to the seaman, tempest to the field, Sorrow to the shepherds, woe unto the birds, Gusts and foul flaws to herdmen and to herds.”

Turns out, there is some science to back up this saying. 

Generally speaking, in the mid-latitudes, weather systems move from west to east, while the prevailing winds are from the west. This means storm systems generally move in from the West, where the sun sets. Also, the colors that you see in the sky are created by the rays of the sun being split into different colors as they pass through the atmosphere and bounce off the water vapor and particulate matter floating in the atmosphere.

The sun’s rays also pass through a greater length of atmosphere at sunrise and sunset than at any other time of day. The moisture vapor, dirt and dust concentrations are maximized in the lowest layers of the atmosphere when the atmosphere is dominated by sinking air (high pressure). 

A red sky suggests an atmosphere loaded with dust and moisture particles. We see the red, because red wavelengths (the longest in the color spectrum) are breaking through the atmosphere. The shorter wavelengths, such as blue, are scattered and broken up. Thus when there is a high pressure system, you see vivid red sunsets and sunrises.

What Does All This Mean For Red Skies at Daybreak? 

When there is a red sky at night, this indicates that the setting sun is sending its light through a high concentration of dust particles. This usually means high pressure and stable air coming in from the West. Most times, good weather will follow. When there is a red sky in morning, it generally indicates that a high pressure system (good weather) has already passed, thus indicating that a storm system (low pressure) may be following to the East. A morning sky that is a fiery red can indicate high water content in the atmosphere, predicting a heightened chance of rain.

This old saying is not always correct, however. On those rare occasions when a weather system is moving from south to north, the weather systems and their associated clouds travel in that direction, and the saying does not hold. Also near both of the earth’s poles, the prevailing winds are generally from east to west, so the saying doesn’t work there.

But for most of us, most of the time, paying attention to a red sky in both morning and evening can help us properly prepare.