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Apr 19, 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.
Sep 18, 2017 · The 2019 fall equinox—also called the autumn equinox—takes place on Monday, September 23, 2019. |The fall equinox is not on the same day each year, though it always falls between September 21...
Fall 2024 Dates. According to the astronomical definition, fall begins with the autumnal equinox. In the Northern Hemisphere, it's the September equinox; south of the equator, it is the equinox in March.
Sep 22, 2022 · Fall starts at 9 p.m. ET Thursday, a day officially known as the autumn equinox. Both equinoxes and solstices only happen twice a year — the first days of fall and spring are equinoxes,...
In the Northern Hemisphere, the March equinox is called the vernal or spring equinox while the September equinox is called the autumnal or fall equinox. In the Southern Hemisphere, the reverse is true. During the year, equinoxes alternate with solstices.
The March and September equinoxes mark the beginning of the spring and autumn seasons on Earth, according to one definition. The equinox in September is the start of fall in the Northern Hemisphere and the beginning of spring south of the equator. Equinox and solstice dates—years 1-2149.
The autumnal equinox occurs in September each year, and in the northern hemisphere the date marks the end of summer and beginning of autumn. The Earth is tilted on its axis. This means that the Sun illuminates the northern or southern hemisphere more depending on where the Earth is along its orbit.
The equinox may be taken to mark the end of astronomical summer and the beginning of astronomical autumn (autumnal equinox) in the Northern Hemisphere, while marking the end of astronomical winter and the start of astronomical spring (vernal equinox) in the Southern Hemisphere.
The September equinox occurs sometime between September 21 and 24. 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.
