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Red Sky in the Morning, Sailors Take Warning… And Other Nautical Lore Sayings

Basil Karatzas
Total Views: 6498
January 6, 2014

Ever since people tried to navigate the seaways, the prevailing weather has always been very crucial to the success of expeditions. To steer away from trouble like storms and hurricanes, obviously, but also to put to service natural resources long before wind and solar energy were standard terms. With tall ships completely dependent on wind to carry on with their businesses, the understanding of trade winds was the obvious subject of ‘weather forecasting’. Thus, early on, a thorough understanding of and a diligent attempt to forecast the weather elements had to be part of any good navigator’s skill set.

Since humans’ early records to understand the weather, from Aristotle’s Meteorologica around 340 B.C., a philosophical treatise with theories about the formation of rain, clouds, hail, wind, thunder, lightning, and hurricanes, meteorology has evolved into a highly quantitative science to model the movement and interaction of natural elements; think of the Earth as a huge sphere of 12,800 kilometers (8,000 miles) in diameter covered with a 40-kilometer skin of various gases, whose concentration varies both spatially and temporarily. Keeping in mind that this sphere has a bumpy surface and is rotating all the time, its tilt about the vertical access varying with the season, and also, that this sphere is heated from 150 million kilometers (93 million miles) away with about eight million quadrillion BTUs of solar energy each year reaching its surface (about 20,000 times the energy consumed by all human activity in a year), thus there is an always changing interaction among the factors determining the weather. Long before the National Oceanic and Atmospheric Administration (NOAA) in the US and the Met Office with the Shipping Forecast on BBC’s Radio 4 in the UK, sailors and navigators were crystallizing shortcuts of weather patterns to become weather lore about the appearance of the sky, the shape and type of clouds, the conditions of the atmosphere, and the direction of the winds.

At sunrise and sunset, sunlight is set low on the horizon and travels disproportionally longer distance in the lower atmospheric strata in order to reach the earth surface; thus, sunlight spending more time traveling the atmospheric strata determine the weather, and thus providing more clues for its forecast. At noon, sunlight hits the surface of the Earth vertically – at least at the Equator – penetrating uniformally all atmospheric strata, and providing less of a clue about weather changes.  Preponderance of dry dust particles in the air is a proxy of lack of water vapors in the air (predecessor to rain), and thus dry air particles act as a prognosticator for lack of immediate raining.

In the Northern Hemisphere and around the mid latitudes (‘Horse Latitudes’, where becalmed vessels often threw overboard horses due to lack of water onboard the vessels), usually prevailing winds move from west to the east; whether easterly moving dry dust particles were located westerly or easterly to the observer, it has been a fair quick rule of thumb about weather forecasting.

Based on these rudimentary principles, here are few interesting nautical weather sayings for old salts and landlubbers alike:

Red sky at night, sailor’s delight, 

Red sky in the morning, sailors take warning.

Variations of the theme:

Evening red and morning gray, help the traveler on his way.

Evening gray and morning red bring down a rain upon his head.

Orange or yellow, can hurt a fellow.

These are perennial favorites of weather sayings with interesting scientific explanation behind it: in the mid latitudes of the Northern Hemisphere, typically weather moves from west to east, blown by the westerly trade winds, meaning that storm systems generally move in from the West.

The colors we see in the sky are due to the rays of sunlight being split into colors of the spectrum as they pass through the atmosphere and ricochet off particles and water vapor in the atmosphere. The amount of dust particles and water vapor in the atmosphere are good indicators of weather conditions. They also determine which colors we will see in the sky.

During sunrise and sunset, the sun is low in the sky and it transmits light through the thickest part of the atmosphere. A red sky suggests that lower atmospheric strata are loaded mainly with dust particles (when atmospheric pressure is high, the lower air holds more dust than water vapors) and low in water vapor concentration.  When we see a red sky at sunset, this means that the setting sun is sending its light through a high concentration of dust particles. This usually indicates high pressure and stable air coming in from the west, meaning that effectively good weather will follow. 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.

A red sunrise reflects the dust particles of a system that has just passed from the west. This indicates that a storm system may be moving to the east. If the morning sky is a deep fiery red, it means a high water content in the atmosphere. So, rain is on its way.

A red sky in the morning can be caused by the dawn light bouncing off cirrus ice crystals in the upper atmosphere. Cirrus clouds can be at the leading edge of a frontal system and so this can also work to signal poor incoming weather.

This weather saying has been referred to in the Bible (Matthew XVI: 2-3,) when Jesus said to the fishermen, “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.”

Several centuries later, Shakespeare in his play Venus and Adonis says: ‘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.’

A comparable saying, incorporating the gray color has it as:

The evening red and morning gray

Are sure signs of a fine day, 

But the evening gray and the morning red,

Makes the sailor shake his head.

Gray sky at night means that the western air is filled with moisture and it will likely rain soon.

Based on similar scientific analysis, also:

A rainbow in the morning gives you fair warning.

In the morning, in the northern hemisphere a rainbow out to the west is caused by the sun in the east refracting on water droplets to the west, similarly to producing red skies. And moisture in the air will be heading east likely to produce rain.


Rainbow to windward, foul fall the day; 

Rainbow to leeward, rain runs away.

A rainbow from where the wind is blowing (from the west, usually, in the Northern Hemisphere) is indicating that water vapors are closing in as they are pushed with the wind, whereas a rainbow to the direction the wind is blowing (leeward), it means that water droplets have already passed the weather observer.

Related to rainbows, there is the saying of:

When the sun shines while raining, 

it will rain the same time again tomorrow.

The incident of raining while the sun is shining is called ‘sun shower’ or ‘sunshower’ and often accompanied by the formation of a rainbow.  As per rainbow explanations above, rain from westerly winds is still in the cards.

Mackerel sky, not 24 hours dry, 

Or its variation:

Mackerel sky, mackerel sky, 

never long wet, never long dry.

Or, another variation:

Mackerel sky (or scales) and mares’ tails, make lofty (or tall) ships carry low sails (or, Make tall ships take in their sails).

Mackerel or fish scale cloud formations are high, thin cirrocumulus clouds formed by shifting wind directions and high speeds and are typical of an advancing low pressure system or an approaching storm system or front.

‘Mare’s tails’ is a term used to describe those high cirrus clouds that are caused by strong winds high in the air.

So it stands to reason that if you have a Mackerel sky and mares’ tails together, it is going to be wet and windy.

When a halo rings the moon or sun, 

Rain’s approaching on the run (or, The rain will come upon the run).

or, its variation:

If there is a halo round the sun or moon, 

then we can all expect rain quite soon.


A ring around the sun or moon, 

means that rain will come real soon.


Halo around the sun or moon, rain or snow soon.

A ring or halo around a bright object like the sun or the moon is caused by refraction of the light through the ice crystals of high cirrus (cirrostratus) clouds.  The presence of these ice crystal clouds is often a sign that a weather front is on its way probably bringing rain and the brighter the circle, the greater the possibility. Cirrus can be the first cloud to appear ahead of a front. The U.S. Weather Service confirms that rain follows about 75 percent of sun halos and about 65 percent of moon halos.

Sun sets Friday clear as bell, 

Rain on Monday sure as hell.

Unknown explanation, and we will be obliged hearing any comments and suggestions on the origin of this expression.

If clouds are gathering thick and fast,

Keep sharp look out for sail and mast, 

But if they slowly onward crawl, 

Shoot your lines, nets and trawl.

When the wind is blowing in the North

No fisherman should set forth, 

When the wind is blowing in the East, 

‘Tis not fit for man nor beast, 

When the wind is blowing in the South 

It brings the food over the fish’s mouth, 

When the wind is blowing in the West, 

That is when the fishing’s best!

With the approach of a low pressure front, easterly winds typically pick up, uncomfortably warm, dry, and dusty in the summer and bitterly cold in the winter.  Northerly winds, which follow around a low, are cold and blustery.  Sailing in conditions of northerly winds requires expertise and a sturdy vessel capable of handling heavy seas.  Southerly winds typically bring warmer temperatures, and though they may not feed the fish, they do provide pleasant fishing weather.  The best is to have a westerly wind blowing since it is likely to persist for some time, the weather should remain fair and clear, and the wind should be relatively constant.

Beware the bolts from north or west;

In south or east the bolts be best.

Meaning that storms to port going North that the storm is coming your way (from the west), while storms to starboard have passed.

A wind from the south has rain in its mouth.

On occasion attributed to Benjamin Franklin, a wind from the south usually brings rain and precedes a cold front.

When rain comes before the wind, halyards, sheets and braces mind,

But when wind comes before rain, soon you may make sail again.

or similarly,

With the rain before the wind, stays and topsails you must mind,

But with the wind before the rain, your topsails you may set again.

Winds occur when two masses of air of different pressure come into contact; for westerly prevailing winds in the Northern Hemisphere, winds before the rain indicated that the two masses of air are already in contact and thus the strong winds, with the rain following from the westerly winds. However, rain, prior to the winds, is indicative of westerly winds blowing to the east without yet reaching the weather front and creating a storm.

No weather’s ill, if the wind be still.

Typically, strong winds occur near weather fronts (frontal boundaries) where two masses of air of different pressures come into contact. Winds tend to be stronger near these frontal boundaries. When the wind is still, it tends to be toward the center of high pressure or the center of an air mass, and thus no ‘weather illness’.  Calm conditions, especially with clear skies, indicate a high pressure area and lack of any phenomena typically associated with weather, such as clouds, wind, and precipitation.  However, calm conditions may also result from a circumstance known as ‘the calm before the storm’, when a large storm cell to the west is sucking up the surface wind in its updraft before it arrives.  This situation is readily apparent by looking to the west for he approaching storm.


If clouds are gathering thick and fast,

Keep sharp look out for sail and mast, 

But if they slowly onward crawl, 

Shoot your lines, nets and trawl.

The sudden storm lasts not three hours 

The sharper the blast, the sooner ’tis past. 

When at weather fronts masses of air of different pressure and temperature forcefully interact, usually such forceful interaction lasts only for a few hours since a new approximate equilibrium of barometric pressures is achieved and thus mitigating the forcefulness of the ‘blast’.

Clear moon, frost soon.

or, similarly,

Cold is the night when the stars shine bright.

When there are no clouds to obscure the moon, there are no clouds to ‘blanket’ the earth’s surface and retain any heat that the earth absorbed during the day so, the surface will cool rapidly on a clear night.

If the new moon holds the old moon in her lap, expect fair weather.

When the new moon can be seen along with the outline of the rest of the moon (‘the old moon’) as in a shadow, then the air must be clear and stable enough for us to see faint objects in the sky. Thus, it means that the weather is fair and is likely to stay that way for a while.

The higher the clouds, the better the weather

For cumulus clouds, nice little woolpacks, with high bases – around 4000 feet or more, rain is unlikely. Similarly, for mackerel appearance clouds (cirrocumulus clouds) with no mare’s tails, then again, the weather looks set fair. These clouds generally indicate both dry air and high atmospheric pressure – usually associated with fair weather. Lowering ceilings indicate rain. However, ahead of a warm front, high cirrus clouds will be spreading high across the sky, a fore-runner of rain some hours later.

A piece of seaweed hung up will become damp before it rains.

As seaweed naturally absorbs water, as atmospheric humidity increases before it rains, dry seaweed gets damper easier and faster, and thus the ‘science’ behind the saying.


When ropes twist, forget your haying.

Natural hemp ropes and rigging have a tendency to twist as humidity rises as they get damper with water vapors from the atmosphere, thus indicating that rain will follow soon.

Similarly in terms of explanation,

When the chairs squeak, it’s of rain they speak.

Besides earthy inanimate objects having weather predicting powers, also animals, birds and fish have been known to have tried their luck with forecasting the weather:

Seagull, seagull, sit on the sand,

It’s a sign of rain when you are at hand (or, It’s never good weather when you’re on the land).


When sea-gulls fly to land, a storm is at hand.

Anecdotal evidence suggests that animals can sense miniscule changes in the environment and their actions accordingly can predict the weather. It’s not always clear how animals exactly sense or interpret changes of atmospheric pressure or impending storms, etc, and how their sensory reception can come to their survival instincts. In general, birds and animals roost/being nothalgic more during periods of low atmospheric pressure. Before a hurricane, flocks of birds will be seen roosting; taking off may be harder when the pressure is low or the air is thinner because the natural updrafts are lessened.

Sharks go out to sea at the approach of a wave of cold weather.

Several studies have shown that sharks are known to move to deeper waters before hurricanes and storms, seeking better protection from strong waves and jeopardizing getting launched on land.

When porpoises sport and play, there will be a storm.

Porpoises are aquatic mammals similar in appearance to dolphins; porpoises are not successfully kept in captivity like dolphins. No much explanation is available why these animals, and also land animals and pets, get more playful before severe weather.  Any suggestions or explanations, we will be thankful to hear.

A backing wind says storms are nigh, but a veering wind will clear the sky.

A backing wind is a wind that turns counter-clockwise with height, while a veering wind is a wind that turns clockwise with height. A backing wind is associated with cold air advection and dynamic sinking (CCBC or CounterClockwise, Backing, Cold air advection). Ahead of a warm front, the wind will back from W or NW to SW, S and even SE. So, this can be a good predictor although not all backing winds will presage a warm front. As a cold front passes, winds will veer from a SW’ly point ahead of the front to NW behind. So, in this case, the wind veer (CVW or Clockwise, Veering, Warm air advection) will be as or after the front has passed. Winds back behind cold fronts.

If wooly fleeces deck the heavenly way, be sure no rain will mar a summer’s day.

Fleecy, wool-like white clouds are only a few hundred feet thick, indicating that they have barely developed due to condensation. As such, they are a sign the atmosphere is still relatively stable.

When boat horns sound hollow,

Rain will surely follow.

Sound travelling far and wide, 

a stormy day betide.

Sound travels faster in the water than in the air, and a little bit faster in humid rather than in dry air. Also, sound is absorbed to the greater extent when traveling through humid air rather than dry air. Thus, sounds in humid days – days proceeding rain, have a hollow (echo-y) effect and travel faster.

When the stars begin to huddle, the earth will soon become a puddle.

As water vapors and humidity increase in the air, in advance of rainy weather, smaller stars on the sky cease to be visible, while bigger, brighter ones overwhelm the sky and shine with a blur or a corona around them (‘fogginess’), giving the impression of cluster of stars rather individual stars.

When the bubbles of coffee collect in the center of the cup, expect fair weather. When they adhere to the cup, forming a ring, expect rain. If the bubbles separate without assuming any fixed position, expect changing weather.

Although our own empirical evidence seems to confirm this weather saying, while sailing or ashore, we have had hard time finding a logical explanation. But, as they say, it’s usually the small things in life that defy easy explanation; after all, it took Albert Einstein himself a whole doctoral dissertation in 1905 on the hydrodynamic derivation of a relation between the coefficients of viscosity of a liquid with and without suspended particles to mathematically explain how sugar dissolves in coffee; we regret that after his dissertation went on to publish with months of his dissertation his next seminal work on Brownian motion, and didn’t dedicate more brain power on the bubbles at a surface of a coffee cup!  Probably, we will have to wait for the next genius for a mathematical formula!


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