If you have ever lived in a coastal city you will have heard the phrase “Red sky at night sailors delight. Red sky at morning sailor take warning,” used in casual conversation to predict the upcoming weather.
This phrase has existed for hundreds of years and has been referenced by many famous historical figures including Shakespeare. Like many folk lore or old wives tales this saying does come from a very basic interpretation of the world around us. This phrase is based on scientific principles relating to the materials that make up the earth’s atmosphere, how we see visible light, and how weather or storms are formed.
So how does this work? Let’s break it up: visible light (what we see with our eyes) is basically made up of the colors red, orange, yellow, green, blue, indigo and violet (ROYGBIV). Simply put, the colors that we see in the sky are created by rays of light that are being broken up into those specific colors by bumping into little teeny tiny objects in the atmosphere: dust, water droplets, you name it! Now in this situation, of “red sky” instead of our normal “blue sky,” there are a lot more the dust particles or water droplets in the atmosphere. This larger amount of dust and water in the air is generally a sign of a change in air pressure.