Fall arrives with the autumnal equinox Saturday night

Fall begins at precisely 9:54 p.m. Saturday — the moment of autumnal equinox.

At that time, the tilt of Earth’s axis will be directed neither toward nor away from the sun, giving equal light to the northern and southern hemispheres.

In the Southern Hemisphere, it’s the moment marking the beginning of spring.

This graphic shared by a National Weather Service office in North Dakota helps illustrate why:

At the equinox, day and night are roughly equal around the world, but not precisely. That’s in part because Earth’s atmosphere bends the sun’s light and allows it to be seen before and after the center of the sun’s face has technically risen or set.

The length of the day also varies by location. On Saturday, the sun will be “up” for about 12 hours, 9 minutes in Baltimore, but about two fewer minutes in Honolulu and five minutes longer in Anchorage, Alaska.

The first day with less than 12 hours of daylight in Baltimore comes Wednesday.

sdance@baltsun.com

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