The first day of fall is here, as the autumnal equinox is Tuesday. Get ready for sweater weather.

Goodbye sweat stains. Hello pumpkin spice.

Our long, hot summer is finally coming to an end on Tuesday, Sept. 22 with the autumnal equinox, which marks the beginning of fall in the Northern Hemisphere.

Autumn arrives Tuesday at 9:30 a.m. EDT (that's 8:30 a.m. CDT, 7:30 a.m. MDT and 6:30 a.m. PDT).

At a precise moment each September, on either the 21st, 22nd or 23rd, the sun is directly above the equator, marking the exact time of the autumnal equinox here in the Northern Hemisphere.

Below the equator in the Southern Hemisphere, it's known as the vernal or spring equinox and marks the beginning of spring. So if you're in need of more guaranteed warmth and sunshine in the months ahead, head way down south to countries such as Argentina, South Africa or Australia.

'Abrupt, punctuated and spectacular': Foliage forecast shows leaves may change early this year

The word equinox comes from the Latin words "aequalis" and "nox," meaning equal night. On the autumnal (and the spring) equinox, daylight and nighttime are each both roughly 12 hours long over most of the world.

(It's true that day and night aren't exactly 12 hours long on the day of the equinox because the Earth's atmosphere refracts, or bends, light in an optical illusion that brings more daylight than there really is. Because of this, the date when day and night are of equal length is usually a few days after the autumnal equinox.)

Although some people claim that the autumnal equinox is the "official" start of fall, there is no administrative or political organization that actually designates that.

Indeed, though astronomers say summer ends Tuesday, meteorologists and climatologists said summer ended Aug. 31, the final day of the three hottest months of the year (June, July and August).

While the first day of fall is Sept. 22, we won't turn the clocks back until Nov. 1, when daylight saving time ends. The clocks are turned back at 2 a.m. by one hour. That means sunrise and sunset will be one hour earlier – and you'll get an extra hour of sleep.

Dual disasters: How is climate change worsening wildfires and hurricanes?

This article originally appeared on USA TODAY: First day of fall 2020: Autumn equinox is Sept. 22 Northern Hemisphere