Event
September 22, 2021
6:30 p.m. – 9:30 p.m.
Online

Autumnal Equinox – Sunset

Join us online at sunset to mark the start of Autumn!

Autumnal Equinox - Sunset

Griffith Observatory marks the start of autumn in the Northern Hemisphere with a live online talk focused on the location of the setting Sun on the western horizon. Observatory staff will discuss the meaning of the equinox and how the Sun’s changing path across the sky causes seasonal changes.

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/autumn 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 autumn 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.