Summer is almost over. It officially ends at 10:49 a.m. Saturday. That's the moment when the Autumnal Equinox occurs in the Eastern United States, according to the Old Farmer's Almanac.

The Alamanac explains what's happening:

On the first day of fall—the autumnal equinox—day and night are each about 12 hours long (with the actual time of equal day and night, in the Northern Hemisphere, occurring a few days after the autumnal equinox). The Sun crosses the celestial equator going southward; it rises exactly due east and sets exactly due west.

Days and nights also have equal length in the spring equinox, too. On Saturday, the sun will rise in McLean at 6:56 a.m. and set at 7:07 p.m.

How are you celebrating Fall?