Day and night get equal billing as fall equinox arrives. Here are 3 things to know Science Sep 22, 2025 8:00 AM EDT

Day and night will get equal time for a brief moment Monday as much of the world heads into fall.

The autumnal equinox arrives Monday, marking the start of the fall season for the Northern Hemisphere and the spring in the Southern Hemisphere. On the equator, the sun will be directly overhead at noon. Equinoxes are the only times when both the north and south poles are lit by sunshine at the same time.

READ MORE: Today is the first day of fall. Here’s why

In the Northern Hemisphere, sunlight will gradually diminish each day until the winter solstice on Dec. 21.

Equinoxes have been marked and celebrated worldwide for centuries. The fall equinox is often connected with h

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