It's almost time to fall into fall, though in many parts of the country, it feels like we're already there. There are specific times when the astronomical seasons officially turn over -- for fall, it's the autumnal equinox.

During an equinox, places around the globe experience nearly equal amounts of daytime and nighttime. The second occurrence this year happens on Sunday.

The autumnal equinox on Sept. 22 marks the start of fall, bringing equal day and night in the Northern Hemisphere.