crepuscular rays

{{Short description|Sunbeams that originate when the Sun appears to be just below the horizon}}

{{Wiktionary|crepuscular ray}}

File:Sun_over_Lake_Hawea,_New_Zealand.jpg shining through clouds, giving rise to crepuscular rays over Lake Hāwea, New Zealand]]

Crepuscular rays, sometimes colloquially referred to as god rays, are sunbeams that originate when the Sun appears to be just above or below a layer of clouds, during the twilight period.{{cite book |url=https://books.google.com/books?id=ZQOJGerV2IcC&pg=PA77 |title=Out of the Blue: A 24-Hour Skywatcher's Guide |first=John|last= Naylor |publisher=Cambridge University Press |year=2002 |pages=77–79 |isbn=9780521809252}} Crepuscular rays are noticeable when the contrast between light and dark is most obvious. Crepuscular comes from the Latin word {{wikt-lang|la|crepusculum}}, meaning "twilight".{{cite web |url=http://www.weatherscapes.com/album.php?cat=optics&subcat=crepuscular_rays |title=Crepuscular rays |first=Harald|last=Edens |publisher=weatherscapes.com |access-date=2011-11-01}} Crepuscular rays usually appear orange because the path through the atmosphere at dawn and dusk passes through up to 40 times as much air as rays from a high Sun at noon. Particles in the air scatter short-wavelength light (blue and green) through Rayleigh scattering much more strongly than longer-wavelength yellow and red light.

Loosely, the term crepuscular rays is sometimes extended to the general phenomenon of rays of sunlight that appear to converge at a point in the sky, irrespective of time of day.{{Cite web|url=https://www.atoptics.co.uk/atoptics/ray1.htm|title = Crepuscular Rays| date=16 September 2023 }}{{Cite web|url=https://www.weatheronline.co.uk/reports/wxfacts/Crepuscular-rays.htm|title = Weather Facts: Crepuscular rays | weatheronline.co.uk}}

A rare related phenomenon are anticrepuscular rays which can appear at the same time (and coloration) as crepuscular rays but in the opposite direction of the setting sun (east rather than west).