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Everything to know about the autumnal equinox — the first day of fall

It's a big weekend for transitions, as Saturday, Sept. 23 marks the official start of fall and the beginning of Libra season astrologically.
/ Source: TODAY

After a noticeably hotter-than-average summer, fall has finally arrived.

The autumnal equinox, which formally occurred Sept. 23 at 2:50 a.m. ET, marked the start of the fall season in the northern hemisphere, as well as the beginning of the astrological Libra season.

With October on the horizon and football season in full swing, the official seasonal transition aligns with the crisp, cool air much of the United States is starting to experience.

Here's a breakdown of the equinox and what to expect this upcoming fall season.

What is the autumnal equinox, and how long are the days now?

The word “equinox” is derived from the Latin words for “equal” and “night,” given that the daylight and nighttime hours on these days are nearly equal.

Whether the day and night are equal length, however, depends on location, according to the Old Farmer's Almanac. Though despite a matter of minutes, each half is approximately 12 hours.

After this day, the days become shorter and the nightfall comes sooner until the winter solstice Dec. 21, at which point the days will start to get longer.

Autumn weather in Bremen
Fall is here!Getty Images

When will it feel like fall?

October will likely bring normal or cooler-than-average temperatures across most of the U.S., according to the Old Farmer's Almanac.

Areas around the Northeast and Great Lakes, as well as from the Midwest and the Plains through the Rockies into the Pacific Southwest, could be warmer than previous years.

The Great Lakes, Ohio Valley, Desert Southwest and Hawaii could also see above average amounts of rain this October, meteorologists predict, though much of the country will remain normal.

In November, meteorologists predict New England will be cooler than average, though most of the eastern portion of the country will be warmer.

As for the upper Midwest to the northern Plains and into the Rockies, temperatures will likely be near or below normal. Whereas along much of the West Coast, aside from Hawaii and Alaska, meteorologists say temperatures will be cooler than previous years.

Areas around Ohio and the Tennessee Valleys, western Great Lakes, upper Midwest and the Plains could see more rain, though much of the Northeast should be drier in November. The I-95 corridor, meteorologists say, should be stormier.

In the central Gulf Coast and most of the Southeast, as well as from the Southwest through the Rockies, conditions will likely be wetter, according to meteorologists. However, the Pacific Northwest and Florida are expected to be drier than average.

What are the other astrological events this season?

The autumnal equinox and Libra season aren't the only transitions happening this season. Here are some more events to keep in mind.

  • Super fall harvest moon in Aries: Friday, Sept. 29
  • Mercury enters Libra: Wednesday, Oct. 4
  • Venus enters Virgo: Sunday, Oct. 8
  • Pluto ends retrograde in Capricorn: Tuesday, Oct. 10
  • Mars enters Scorpio: Thursday, Oct. 12
  • Solar eclipse in Libra: Saturday, Oct. 14
  • Mercury enters Scorpio: Sunday, Oct. 22