Autumn Equinox

The first day of autumn often called fall (September equinox or autumnal equinox) is when the sun shines directly on the celestial equator passing from north to south and the length of day and night are almost the same. This is referred to as astronomical autumn or the September equinox.


Astronomical autumn starts at different times around the planet because of the different time zones as related to Coordinated Universal Time (UTC, same as Greenwich Mean Time based on the Royal Observatory in Greenwich, London [1]). For countries located west of UTC your autumn will start earlier than countries located east of UTC.