Crepuscular rays, often referred to as “sun rays” or “God rays,” are striking beams of sunlight that appear to fan out from the location of the sun, typically seen during the early morning or late evening hours. These rays are formed when sunlight streams through gaps in clouds, mountain peaks, or other obstacles, creating visible columns of sunlit air. What we’re seeing is actually sunlight scattered by particles in the atmosphere, such as dust or moisture. Although they seem to radiate outward from a single point near the Sun, this is an optical illusion caused by perspective similar to how train tracks appear to meet at the horizon even though they remain parallel. The term “crepuscular” comes from the Latin word crepusculum, meaning “twilight,” which is when these rays are most often visible due to the lower angle of the Sun and the increased likelihood of atmospheric scattering.

Interestingly, there’s a lesser-known counterpart to this phenomenon: anti-crepuscular rays. These rays appear on the opposite side of the sky from the Sun, converging toward the anti-solar point that is, the point directly opposite the Sun from your viewpoint. While they are also made up of parallel beams of sunlight, their appearance in the eastern sky at sunset or in the western sky at sunrise is again due to perspective. Anti-crepuscular rays are often subtler and more difficult to spot than their crepuscular counterparts, but under the right atmospheric conditions, they can stretch across the entire sky, forming a beautiful visual connection between the two horizons. Together, these phenomena are a fascinating reminder of the interplay between light, atmosphere, and human perception.

Click on any of the images below for examples of crepuscular rays and anti-crepuscular rays and a better view and additional information.