The predominant color of the sky on a clear day is blue. This phenomenon is due to a process called Rayleigh scattering, where shorter wavelengths of light, such as blue, scatter more than longer wavelengths like red. When sunlight enters the Earth's atmosphere, the blue light is scattered in various directions by gas molecules and small particles, causing the sky to appear predominantly blue to the human eye. During sunrise or sunset, the sky can take on shades of orange, pink, and purple due to the scattering and filtering of light through a thicker atmospheric layer, but midday typically sees a bright blue sky.