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Astronomical fall arrives Thursday night Here's what that means

The autumnal equinox, when the sun is directly over the equator, began at 9:04 p.m. September 22.
Credit: tt

WASHINGTON — The temps drop as if we flipped a switch. Our first, full day of Fall, Friday will be breezy with highs only in the 60s. The last time we held in the 60s was May 24th. Lows Friday night will be in the 40s in the suburbs. 

Astronomical fall, or the Autumnal Equinox, begins at 9:04 p.m., Sept. 22, 2022.

The Autumnal Equinox is when the sun is directly over the equator, creating equal parts day and night in each hemisphere, and marking the beginning of astronomical fall. However, this event has no impact on the gravitational pull down on Earth - you could stand an egg on its end any time of the year, and nothing will change as far as the egg is concerned. 

While meteorological fall began on Sept. 1, we go into fall while the southern hemisphere heads into spring. 

You might ask why the sunrise and sunset times are not exactly twelve hours apart on the first day of fall. 

The earth’s atmosphere bends the light so there are not exactly twelve hours between sunrise and sunset on Sept. 22 -- that occurs on Sunday, Sept. 26 with a sunrise and sunset time of 6:59. As we move toward winter, the sun’s angle will continue to fall.

The angle of the sun is the key to climate. Yes, the days get shorter and the jet streams start to dip into the continental mainland more often, but the angle of the sun is what drives climate. The lower the angle, the lower overhead, the weaker the sun’s rays will be. 

You might also be asking yourself why the beginning of fall is not the same time and same day every year. The solar year is about 365 and a quarter days so the time and date of spring and of all of the seasons can vary about a day or so.  

Credit: tt


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