The sky's colour mainly depends on the size of the atmospheric particles, their individual wavelengths and the distance they travel before reaching the Earth's atmosphere. What makes the sky blue is the fact that blue has a short wavelength, causin it to be scattered more and thereby making the sky appear blue, when the distance the atmospheric particles travel before they hit the Earth's atmosphere is lenghthened however, these particles are scattered for a longer period of time, allowing red/orange light to be scattered more than blue, making the sky appear red/orange