Red Sky At Night, Sailor's Delight And Other Weather Proverbs Explained

Ever heard the saying, "Red sky at night, sailor's delight"? Before meteorologists busted out forecast models, people made weather predictions based on their observations of the sky and nature — and in some cases even based on what the animals were up to. And because observations don't necessarily rely on scientific studies, we used information from the National Oceanic and Atmospheric Administration (NOAA), NASA, the National Park Service and the Farmer's Almanac to help explain these weather proverbs.

'Clear moon, frost soon'

If you can see the moon clearly, there probably aren't many clouds in the sky. Clouds trap heat from the sun to keep the atmosphere warm. NASA explains it like this: "At night, when there's no sunlight, clouds are still trapping heat. It's sort of like clouds are wrapping Earth in a big, warm blanket." But when the night sky is crystal clear, the Earth's surface cools rapidly because there is no cloud cover to keep the heat in. If the night is clear enough to see the moon and the temperature drops, we may find a frosty morning.

'Red sky at night, sailor's delight'

According to the National Oceanic and Atmospheric Administration, the red sky is a result of the way sunlight is scattered in different weather systems. When we see a red sky at night, it can mean that the setting sun is sending its light through a high concentration of dust particles, which usually indicates high-pressure air coming in from the west. And a high-pressure system generally means pleasant weather.

'Red sky in morning, sailors take warning'

A red sunrise can indicate that good weather has just passed, and can mean that a storm system (low pressure) may be moving in. A morning sky that is a deep red can signal high water content in the atmosphere, meaning rain could follow.

'When leaves turn their back 'tis a sign it's going to rain'

According to the NPS, some trees such as oak and maple grow leaves that curl up when there is high humidity in the air and the wind is blowing strongly — both indicators of an approaching storm. If you go hiking through any scenic beginner trail in America's national parks, keep an eye out for how some leaves react to the weather. 


'If birds fly low expect rain and a blow'

If birds are flying high, the weather is clear and calm. But if they're flying closer to the ground, it could be because the air pressure of a storm system is making it difficult for them to fly at higher altitudes. 

'Mares' tails and mackerel scales make lofty ships carry low sails'

Cirrus clouds are often called mares' tails because of their resemblance to the tail of a horse. Altocumulus clouds appear smaller and broken, giving them the look of fish, or more specifically, mackerel scales. These cloud types tend to precede an approaching storm front by a day or two, and luckily will only bring rain and not some of the strangest things that have rained from the sky.

'Trace in the sky the painter's brush, the winds around you soon will rush'

In this proverb, cirrus clouds are referred to as a "painter's brush." Cirrus clouds look like feathery strokes in the sky, like ones a painter's brush would make, and the clouds are made mostly of ice crystals. Their wispy, natural wonder shape comes from wind currents that spread the ice crystals into strands. The high-level clouds often indicate a change in the atmosphere as a storm system brews.

'When sounds travel far and wide, a stormy day will betide'

The speed of sound can be affected by factors like humidity and air pressure, so this proverb is no weather myth. Sound travels better in higher humidity, and some folklore says English people gauged the chances of rain by how clearly they could hear the sound of church bells ringing. Sound travels better in air that is moisture-heavy than it does in dry air.

'Pale moon rains, red moon blows, white moon neither rains or snows'

In order for raindrops to form, there has to be a dust particle or ice crystal in the air acting as a "condensation nucleus." So if there are a good amount of particles in the air, there is a greater chance moisture will have something to latch onto. That being said, when moonlight passes through air that is filled with dust particles, it appears pale or reddish. But when the air is clear, the moon appears white.

'If it rains before seven, it will clear before eleven'

This proverb is likely based on the weather in the United Kingdom, where it rains a good portion of the year. A morning rain can sometimes indicate that it has been raining all night, which might mean that the skies will clear up as dawn becomes day.

'Tornadoes never strike twice'

Natural disasters are loaded with myths and confusion. And though some folklore might lead people to believe tornadoes never strike twice in the same place, it is not true. According to NOAA, Cordell, Kansas, was struck by a tornado on May 20, three years in a row (1916, 1917, 1918). And once in Arkansas, three tornadoes hit the same church on the same day.

'Lightning never strikes the same place twice'

Similar to tornadoes, people might assume lightning never strikes the same place twice. But you have been warned, because bolts of lightning often strike the same place repeatedly. And if it's a pointy and isolated object like some of the mesmerizing man-mad marvels in America, the odds are even greater. The Empire State Building, for instance, is hit an average of 23 times a year.

'The higher the clouds, the finer the weather'

If you spot wispy thin clouds higher up in the sky than usual (closer to the airplanes), you can generally expect pleasant weather. These types of clouds are called cirrus clouds and hover 5 to 10 miles above the surface. However, if the morning or early afternoon brings smaller puffy cumulus clouds that have flat bases but rounded tops, there's a chance of a roaring thunderstorm forming.

'When dew is on the grass, rain will never come to pass'

If there's dew on the grass in the morning, it could be a sign that it's going to be a clear day. Dew often forms after a cool and clear night. If dew has time to form on the ground overnight, it means the clear skies allowed the earth to cool and water to condense. If the night skies are pleasant, the following day is likely to be cloud-free too.

'Flies bite more before a rain'

This rule does not always apply, and when it does, it has much more to do with humans than actual impending weather. The hot and muggy conditions before a typical rainstorm cause humans to sweat and release body odor, which might attract a larger swarm of mosquitoes, leaving you with itchy bite marks. Instead of being outdoors when it rains, there are lots of other ways to make the most of spring weather.

'If a circle forms around the moon, 'twill rain soon'

Though this one has less to do with the moon than it does cloud cover, here's what the proverb means: The circle that forms around the moon is called a halo, which is formed by either the light from the sun or from ice crystals. Ice crystals form altostratus clouds and cirrostratus clouds, which often indicate rain or snow will arrive within 24 hours. When moonlight shines through a thin layer of cloud cover made up of ice crystals, the light forms into a halo, hence those ice crystals being a good indication of impending precipitation.

'You can tell the temperature by counting a cricket's chirps'

This proverb sounds like a myth, but crickets are accurate thermometers and they chirp faster when it's warm and slower when it's cold. As the temperature rises, the cricket's metabolism also increases and allows the process that triggers the chirps to happen more quickly. Count how many times a cricket chirps in 15 seconds and then add 37. The number you get will be a close estimate of the outside temperature in degrees Fahrenheit.

'If clouds move against the wind, rain will follow'

Clouds that are rapidly moving in a direction against the wind indicates a condition known as wind shear. Wind shears can signal the arrival of a cold front, which usually brings rain as a result. Such dramtically changing weather systems are phenomenons that only happen in the spring.

'If you see a rainbow in the morning, it could mean a storm is on the way'

While an evening rainbow means the rain is probably heading away from you, a morning rainbow means rain is likely coming closer. The sun rises in the east and sets in the west and storms typically move from the west to the east. Since in the morning the sun is in the east, any visible rainbows will be in the west because rainbows are always on the opposite side of the sky as the sun.

'If a pine cone closes up, it means rain could be coming'

A pine cone will react to changes in humidity to protect its seeds from getting drenched in the rain. When it's damp, the scales close up. When it's dry out, the pine cone opens back up again to allow the wind to carry the seeds off. The drier and lighter the seeds are, the farther they will go.