Autumnal equinox Sep 23, 2023

Autumnal equinox

Autumn has officially begun! In the Northern Hemisphere, the autumnal equinox falls on September 23 this year, marking the beginning of autumn and the Earth and Sun"s unique positions. Today is one of the two moments in the year when day and night are equal in length, thanks to the Sun"s location exactly above the Equator. The same celestial phenomenon applies to the Southern Hemisphere, but it is their vernal equinox as they head into spring.

© Stephen Matera/Tandem Stills + Motion

palette

Today in History

Jellies in a world all their own
Sep 23, 2024Sea otter in Prince William Sound, Alaska, USA
Sep 23, 2025Keel-billed toucan, Costa Rica

More Desktop Wallpapers:

Aug 22, 2025Rolling hills of the Palouse, Washington, United States
Oct 1, 2023Lake Bled, Slovenia
Oct 18, 2024Autumn in Central Park, New York, United States
Golden cliffs of deep space
A window to the Pacific
Dec 5, 2025Maya site of Copán
Jan 24, 2024Diamond Beach, Iceland
Dec 4, 2024Navy Day
Bungle beehives
Mar 23, 2025World Meteorological Day
Sep 13, 2025Point Reyes National Seashore, California, United States
Hop into Lunar New Year
May 24, 2024Ordesa y Monte Perdido National Park, Huesca, Spain
Park of the Monsters
Aug 30, 2025International Whale Shark Day
May 19, 2024Vernazza, Cinque Terre, Liguria, Italy
Oct 11, 2023The Painted Hills, Oregon
Apr 10, 2024Dragon waterfall, Venezuela
Dec 11, 2023Huangshan Mountains, China
Sep 23, 2023Autumnal equinox
Dec 25, 2025Merry Christmas!
Reflecting on Christmas
Jul 2, 2025Spine-cheeked anemonefish
The animal kingdoms great migration
Aug 29, 2024Castellfollit de la Roca, Catalonia, Spain
Apr 1, 2025Tree frog, Costa Rica
Nov 11, 2024Banff National Park, Alberta, Canada
Feb 1, 2025European beech forest, Belgium
Stairway to heaven?
Twinkle twinkle, little bugs