Have you ever wondered why the sky is blue during most of the day and isn't any other of the other colors in the rainbow?
The colors we see has to do with light from the sun, the sun's angle in the sky and reflection.
Air molecules act like tiny prisms in the sky. They can reflect different wavelengths of color. Unlike glass prisms though, the air molecules can also absorb certain colors.
During the day, when the sky is high above us in the sky, the shorter wavelengths of color get reflected back to our eyes more easily. In the weather world, we call this type reflection "rayleigh scattering."
Rayleigh scattering works best for shorter wavelengths. The colors blue, indigo and violet have the shortest wavelengths within the visible light spectrum.
During the early morning and twilight hours, the sun is at a lower angle in the sky, and the light takes longer to travel to earth. During those times, longer wavelengths are more easily reflected back to our eyes.
Reds and oranges have the longest wavelengths in the visible light spectrum, so that's why sunrises and sunsets are usually hues of red and orange.
Using meteorology and physics, that is why the sky is blue, and that's how your weather works!