Scattering of light is more pronounced when the size of the scatterer is comparable to the wavelength of the light. At sunrise, the Sun is located near the horizon. Hence, the light has to travel a long distance through the Earth’s atmosphere. At the time of sunrise or sunset, when white sunlight falls on the suspended atmospheric particles, the blue colour light scatters out more in the atmosphere because the size of the atmospheric particles are comparable to the wavelength of the blue colour light, while the red colour light scatters less because it has larger wavelength than the blue colour light. So, the red colour light reaches the eyes of the observer on the surface of the Earth. Hence, when this less scattered red light reaches the eyes of the observer, the Sun and its surroundings appear reddish. At noon, the sun is nearly overhead and the light from the Sun travels a relatively shorter distance. Therefore, at noon, only a little of the blue and violet colour lights are scattered, making the Sun appears nearly white at noon.