# What causes red skies? [duplicate]

This morning, as I was walking to work, I noticed that the skies were different. It had a reddish tint.

What causes this?

## marked as duplicate by Kyle Kanos, user10851, WetSavannaAnimal, John Rennie, MartinJul 17 '15 at 10:07

• It is a duplicate, but what a lovely picture. – John Rennie Jul 17 '15 at 5:58

There is two processes going: absorbtion $A$ and reflection $S$ (scatter). I think that these type of clouds have density which is causing ratio of $S/A$ to be big enough for thin lower border so we could see that red light.