Many will see calendars reference the first day of fall this year to be, Tuesday, September 23, however this year is not an easy year to determine the first day of fall. The official time of the Equinox (the moment when the Sun is positioned directly over the Earth’s equator) is 9:29 pm CDT Monday evening. The reason many reference Tuesday is due to the Universal Time of the Equinox. This year the official time occurs at 0229 UTC September 23. This is why you may see the two days referenced as the first day of fall.
Typically the day of the Universal Time is the day most often references as the first day of fall. During daylight time there is a 5 hour difference between the start of the day for Universal Time to Central Daylight Time. Thus whenever the Equinox occurs early in the day Universal Time, confusion may occur.
During the day of an Equinox, nearly every point on the Earth’s surface has the same sunrise and sunset, (exception is when there is an obstruction to the horizon like a mountain). The autumnal equinox will occur on either the 22nd or 23rd of September.
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