For centuries, people have been attempting to predict the weather.  Sailors, in particular, focus heavily on conditions at sea.  Throughout the years, man’s observations took the form of some interesting proverbs.  Let’s take a look at the science behind these observations.

Red sky at morning,
Sailors take warning;
Red sky at night,

Sailors delight


The explanation for this is quite simple.  A red sunset occurs when you view it through dust particles which are the main ingredient for rain.  Each rain drop has a tiny dust particle inside it.  Weather, for the most part, flows from west to east.  So when you see the red sky at night you are seeing dry weather soon to come.  The dust particles have not developed into rain.  The red sky in the morning is caused by the sun lighting up the cirrus clouds before it has actually risen.  These clouds are generally followed by cirrostratus clouds and lowering frontal clouds which produce foul weather.

Mackerel skies and mare’s tails,
Make all tall ships carry low sails.

If there are just a few high-flying cirrus clouds that resemble mare’s tails then good weather is on its way.  However, when the sky becomes overwhelmed by cirrocumulus or mackerel clouds (resemble rippled sand on a beach) you can expect a storm.  Cirrocumulus clouds frequently appear before a warm front and veering winds which eventually brings precipitation.

A sailor is truly salty once he can manage the helm and sail trim while keeping a weather eye on the horizon for approaching ships and storms.  The clouds that are almost always present in the Caribbean sky give a detailed look into the next 12 hours of weather for the sailor who knows what to look for.  The best way to read the clouds is to know their different types and what each one means:



Rainbow in the morning,
Sailors take warning;
Rainbow at night,
Sailors delight.

The explanation is even simpler than for the previous proverb.  As you remember, storms usually travel from west to east.  If you were to see a rainbow in the morning you are looking at it in the west as the sun shining over your back rises in the east.  If the rainbow is in the west, the storm has not yet passed.  The reverse holds true in the evening.  You will see the rainbow in the east as the sun sets in the west and the storm has already passed you by.

Rainbow to windward, foul fall the day;
Rainbow to leeward, rain run away.

If the rainbow is in the direction of the prevailing wind, then the bad weather has not passed through yet and you should prepare to get wet.  Conversely, if you see the rainbow to the leeward then the storm has already passed and you can enjoy the sights.

Winds that swing against the sun
and winds that bring rain are one.
Winds that swing around the sun
Keep the rain storm on the run.

Again, we rely on the fact that most weather moves from west to east.  Therefore, winds that swing with the sun (east to west) bring good weather while winds that blow against the direction of the sun (west to east), bring bad weather.

When a halo rings the moon or the sun
The rain will come upon the run.

Halos are very good indicators for upcoming weather.  When you look at the sun or moon through a halo, you are looking at it through ice crystals formed in high cirriform clouds.  When the whole sky is covered with these clouds, a warm front is approaching and it will begin to rain soon.

After understanding the scientific reasoning behind them, some of these proverbs are quite plausible, but not always accurate.  Have fun seeing how often they come true for you, but use with caution!