What Does A Red Sky At Night Mean? 

Many European sailors know the saying: Red skies during the night, the sailors delight, and red skies throughout the day. Mysterious, isn’t it? A red sky at night means heavy rains from the west could exist. The ominous color appears when the sunlight comes from the west, and the clouds turn the skies to the east. 

Clouds (and the accompanying weather system) are passing through your spot, so you may expect moderate weather. This article explores the science and folklore behind red skies. We will also briefly discuss sun rays scattering and weather systems. 

TABLE OF CONTENTS:

The Scattering Of Sunlight

Sunlight is an intense beam of light that scatters through the atmosphere. The atmosphere contains clouds, dust, and other particles. These particles scatter sunlight but don't distribute the color wavelengths equally. They spread colors on the shorter wavelengths more than those on long wavelengths. 

The colors on short wavelengths are blue, green, and violet, while those on long are pink, red, yellow, and orange. The clouds primarily radiate blue light because that is the most scattered light. Sunsets in the late evening are often orange, red, and pink, while the sky in the morning is yellow, pink, violet, and blue.

What are weather systems?

Weather systems refer to the development of depressions, the various features within the depressions, and the weather produced. The Coriolis force deflects air to the right front of the north hemisphere². There are high-pressure systems and low-pressure systems.

A high-pressure system, known as an anticyclone, occurs under stable weather conditions. The sinking air under an anticyclone pressure forms an area of higher pressure at the surface.

A weather system also has a front, a boundary between two different types of air masses. Warm fronts refer to an advancing warm air rising over colder air. Cold fronts refer to cold air pushing beneath warmer air at the surface.

The Science Behind A Red Sky at Night

The sky is predominantly blue but changes colors at specific times. It changes at sunrise and sunset. These colors vary from yellow to orange to red. Some researchers have devised an explanation for the red sky at night and the red sky in the morning.  

The color of the sky largely depends on how sun rays scatter through the clouds, and the colors produced by the sun rays are sometimes influenced by dust, smoke, and other atmospheric pollutants.

The intensity of the red sky depends on the dust and smoke in the atmosphere. A red sky at night and in the morning occurs more frequently during the dry season because the wind carries more dust and other particles into the atmosphere.

You see a red sky at night because of the high-pressure system from the west. A red sky at night often signifies that the next day will be fair weather, while a red sky in the morning indicates a high-pressure system from the east. 

A red sky in the morning often means an increased chance of a low-pressure system arriving from the west. It means good weather has passed, and stormy weather is approaching as it moves east towards the rising sun.

For example, a red sky at sunrise in Australia shows fair weather around the east region, while low-pressure systems and bad weather replace it from the west. Stormy weather starts from the west in mid-latitudes because of the earth's rotation.

Weather systems in areas with mid-latitudes are depressions with prevailing winds lasting for 24 hours and a mix of high pressure and fair weather. Sun rays travel through extended clean air paths as the sunset approaches a high-pressure ridge. During this trip, the sun's blue light scatters through the clear air and leaves the red light on clouds above the horizon.

A red sunset or red sunrise also occurs temporarily after rain. In areas with lower latitudes, weather systems move from east to west. Weather systems moving from east to west make it tough to predict the weather with a red sky.

Related Read: Why Is the Sky Yellow? Why Are There Pink Clouds In The Sky?

Red Sky Weather Folklore

Folklores were means of passing information and figuring out how to live life, especially when navigating a weather system like storms. Early English marines traveling to Australia suffered from the treacherous mid-latitudes and high pressure of the northern hemisphere. 

A traditional rhyme that discusses the phenomena¹ is the red sky at night, shepherd's delight. Red sky in the morning, shepherd's warning.

The saying first appeared in the Bible, in the book of Matthew. It is an old warning shepherds use at sunrise and sunset to announce a change in the atmosphere. Red clouds help them avoid herding during storms. 

There is another variation of this old warning rhyme. Sailors mostly use it to denote the weather system as they are sailing through the oceans. The rhyme is: 

Red sky at night, sailors delight. Red sky in the morning, sailors warning. 

Shakespeare also 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 herdsmen to herds.” 

In Matthew 16:2-3, Jesus said, “When in the 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.”

These weather lores help ancient people attend to their daily activities without the weather interrupting them. For instance, the red sky at night is a source of sailors' delight. Red sky in the morning, sailors warning, helps night sailors navigate the rough seas. 

The sea becomes rougher during storms. Red clouds mean the presence of high water content in the atmosphere. A red sky helps morning sailors take warnings and prepare for a storm or rain, while night sailors are happy because red clouds mean the weather is calm. 

Conclusion   

The color of the sky can act as a warning, informing you of the weather conditions. Now that you know you can predict the weather with red clouds, check your weather forecast news or application to see if you are correct. Remember that red clouds as the sun rises in the west means it might rain, while the setting sun beneath red clouds means the weather is stable.