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Find out when fall starts in the Northern and Southern Hemispheres according to astronomical and meteorological definitions. Learn about the equinoxes, the equilux, the day length, the temperatures, and the traditions of fall.
Aug 23, 2024 · autumnal equinox, two moments in the year when the Sun is exactly above the Equator and day and night are of equal length; also, either of the two points in the sky where the ecliptic (the Sun’s annual pathway) and the celestial equator intersect.
- The Editors of Encyclopaedia Britannica
An equinox is when the Sun crosses the Earth's equator and day and night are of equal length. The autumnal equinox is around 23 September in the Northern Hemisphere and marks the start of autumn.
Learn about the September equinox, when the Sun crosses the celestial equator from north to south, and the start of fall in the Northern Hemisphere. Find out the date, time, and facts of this astronomical event and how it affects day and night around the world.
In the Northern Hemisphere, the March equinox is also known as the spring or vernal equinox; the September equinox can be called the fall or autumnal equinox. In the Southern Hemisphere, the names are the other way around.
Sep 20, 2016 · Learn about the astronomical phenomenon of equinox, which marks the start of fall in the Northern Hemisphere and spring in the Southern Hemisphere. Discover how to observe Saturn, the moon, and star clusters in the night sky around the autumn equinox.
The September equinox is when the Sun crosses the celestial equator, heading southward. It marks the start of astronomical autumn in the Northern Hemisphere and the end of astronomical winter in the Southern Hemisphere.
