Why is the sky blue? A clear cloudless daytime sky is blue because molecules in the air scatter blue light from the sun more than they scatter red light. When we look towards the sun at sunset, we see red and orange colors because the blue light has been scattered out and away from the line of sight. The white light from the sun is a mixture of all colors of the rainbow. This was demonstrated by Isaac Newton, who used a prism to separate the different colors and so form a spectrum. Listen for the blue sky jay in the chorus :)