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What to Know About the Fall Equinox

Why day and night aren't exactly equal

After record heat baked much of the Northern Hemisphere this summer, the arrival of fall and cooler temperatures may come as a relief to many. The change in seasons is marked by the autumnal equinox, which arrives Saturday at 2:50 a.m. Eastern time.

The autumnal (or fall) equinox is the halfway point between the summer and winter solstices and marks the precise moment when the sun appears directly over the Earth’s equator.

The exact time of the equinox varies each year. While the autumnal equinox usually occurs on Sept. 22 or 23, it occasionally falls outside those dates. An early Sept. 21 equinox last happened more than 1,000 years ago, but it will happen again later this century — in 2092 and 2096, according to On the other hand, a late Sept. 24 equinox occurred as recently as 1931 but won't happen again until 2303.

Please select this link to read the complete article from The Washington Post.

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