Did you know that ghosts in the clouds and spiders invading your house can tell you a lot about the weather? With Friday 13th upon us, let's explore some of the best spooky weather omens.

Red sky in the morning

The phrase ‘red sky in the morning shepherds/sailors warning’ is probably one of the most well-known weather omens in the world. The idea of a red morning sky being a sign of impending bad weather was referenced in William Shakespeare’s 1593 poem Veus and Adonis:

“Like a red morn, that ever yet betoken'd

Wreck to the seaman, tempest to the field,

Sorrow to shepherds, woe unto the birds,

Gusts and foul flaws to herdmen and to herds.”

This weather lore has stood the test of time because it is true in some cases. As most weather systems in the mid latitudes move from west to east, a sky is red in the morning can mean the air to the east is full of dust and other particles, due to a stable high pressure system. With this stable weather already to the east, it can mean that rain-bearing low pressure is approaching from the west.

The morning sky can also appear red when light from the rising sun hits the underside of high cloud, which is usually composed primarily of tiny ice crystals. As high cloud can precede thicker rain-bearing clouds, this can mean that wet weather is on the horizon.

So, if you see a red sky in the morning, it can mean that rain or storms will arrive later that day.

Spider invasion

Arachnophobes beware! Spiders have been known to come into houses during period of dry weather in search of water. On rare occasions, they might even lay eggs and inside the house if it is a favourably warm and humid environment. Scientists also believe that low atmospheric pressure can be a trigger for baby spiders to emerge from their egg sacs.

Ghosts in clouds

The atmosphere can produce a wide range of spectacular optical phenomena when light from the sun interacts with water, ice and other particles in the sky. Some of the most well-known examples of this are rainbows, fog bows and colourful sunsets and sunrises.

But one of the spookier optical illusions created by the sin is the Brocken spectre, which looks like a giant ghost in a cloud.

Image: A Brocken spectre in Europe’s Carpathian Mountains

A Brocken spectre occurs when a person’s shadow is cast onto nearby fog or cloud. It usually occurs when the viewer is on a tall building or mountain, looking down on fog or cloud, with the sun directly behind them. When a Brocken spectre occurs at the right angle, it can make the shadow look like a giant ghost in the sky.

Image: Broken spectre in the Tatra Mountains in Slovakia

If you know of any more spooky weather omens, we would love to hear about them. You can share them with us by searching for @weatherzone on Facebook, Twitter or Instagram.