Sunlight looks white, but it is made of many colors. When sunlight enters Earth’s atmosphere, it meets tiny parts of air. The light then scatters in different directions.
Blue light scatters more than red light because it has a shorter wavelength. This scattered blue light reaches our eyes from all parts of the sky. That is why the sky usually looks blue during the day.
At sunset, sunlight travels through more of the atmosphere before it reaches us. Much of the blue light scatters away, so we see more red and orange light. This is why sunsets often have warm colors.