Event
September 22, 2021
12:00 p.m. – 1:15 p.m.
Online

Autumnal Equinox – Local Noon

Join us online at local noon to mark the start of Autumn!

Autumnal Equinox - Local Noon

Griffith Observatory marks the start of autumn in the Northern Hemisphere with a live online talk focused on the Sun as it reaches its highest point in the sky at local noon. Observatory staff will discuss the meaning of local noon and show how the Sun’s changing path across the sky causes seasonal changes.

This year the equinox occurs at 12:21 p.m. PDT and local noon is at 12:46 p.m. PDT

Autumn begins in Earth’s northern hemisphere at 12:21 p.m. PDT, today. Spring begins in the southern hemisphere at the same time. The September/autumnal equinox is the moment when the Sun crosses the celestial equator (the projection of Earth’s equator into space) from north to south. From the autumnal equinox until the start of winter – the winter solstice in December – days will get shorter, and the noon elevation of the Sun will decrease. This happens because the Earth’s axis is tilted 23½ degrees to its orbit. Day and night are of equal length today.