Hi,

Blue color have shorter wavelength than red, so according to Rayliegh scattering law sunlight scatters off of the molecules of air. Because blue light is scattered more than any other color in the spectrum, the sky appears blue to human eyes.

Thank You.

Hi! The sky is blue in color because of  the scattering phenomena. Basically, sunlight is scattered by gases and molecules in all direction in the Earth's atmosphere. Blue light is scattered more than other colors because it travels as shorter, smaller waves as a part of the several different waves of light, especially compared to red, which actually has a longer wavelength. This is why the color of the sky appears to be blue.

Hope this answered your query!