Autumnal equinox Sep 23, 2023

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:

Jun 17, 2026Tremola Road on the Saint Gotthard Pass in Airolo, Switzerland
Jan 7, 2025Moeraki Boulders, South Island, New Zealand
Mar 11, 2024Sleeping koala
An ocean of stars above the desert
May 16, 2025Hawa Mahal, Jaipur, Rajasthan
Nov 7, 2025Polar bear in Churchill, Manitoba, Canada
Apr 18, 2024International Day for Monuments and Sites
Jan 18, 2024Pont Alexandre III, Paris, France
Pearl among the emeralds
Jul 27, 2024Vineyards above the Moselle River, Rhineland-Palatinate, Germany
Apr 17, 2025Andean cocks-of-the-rock, Ecuador
Sep 5, 2023Mount Segla, Senja Island, Norway
May 29, 2024World Otter Day
Apr 27, 2025Coastal redwoods in Redwood National and State Parks, California, United States
The other great barrier reef
Sep 2, 2024Rhino mother and calf, Kaziranga National Park, Assam
Oct 4, 2024World Space Week begins
Nov 23, 2025Fibonacci Day
Feb 8, 2026Corfu at night, Greece
Jun 8, 2026World Oceans Day
Dec 9, 2024Two Guanacos, Torres del Paine National Park, Chile
Mar 8, 2024International Womens Day
An island made from a vow
Dec 13, 2024Christmas market, St. Stephens Basilica, Budapest, Hungary
Apr 21, 2024Great Smoky Mountains National Park, Tennessee, USA
An apex predator
Jun 16, 2025World Sea Turtle Day
Sep 4, 2023Whale shark, Ningaloo Reef, Western Australia
Apr 16, 2026Skagit Valley Tulip Festival
Oct 9, 2023Gwalior, Madhya Pradesh, India