Crepuscular rays are beams of sunlight that have been scattered across the sky, seemingly from the point in the sky where the sun is located.
Light from the rising or setting Sun may be scattered in hazy conditions; caused by dust, smoke and other dry particles in the atmosphere to produce sunbeams known as crepuscular rays. These rays stream through gaps in clouds or between other objects. Although the beams seem to converge at a point beyond the cloud they are actually near-parallel.
Crepuscular rays are usually red or yellow in appearance because the path through the atmosphere at sunrise and sunset passes through up to 40 times as much air as rays from a high midday sun. Particles in the air scatter short wavelength light (blue and green) through Rayleigh scattering much more strongly than wavelength yellow and red light.
Last updated: 5 August 2014