Farewell, flip-flops. And hello pumpkin spice.
Our long, hot summer is finally coming to an end on Monday, Sept. 23, with the autumnal equinox, which marks the beginning of fall.
The exact time of the equinox is 3:50 a.m. EDT (that's 2:50 a.m. CDT, 1:50 a.m. MDT and 12:50 a.m. PDT).
At a precise moment each September, usually on the 22nd or 23rd, the sun is directly above the equator, marking the autumnal equinox here in the Northern Hemisphere.
South of 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.
Need a fall fix? Try leaf-peeping by boat from these 10 great places
The word equinox comes from the Latin words "aequalis" and "nox," meaning equal night. On the autumnal (and the spring) equinox, day and night are both roughly 12 hours long in most of the world.
This will be true Monday from as far north as Utqiagvik (formerly Barrow), Alaska – north of the Arctic Circle – to as far south as Wellington, New Zealand, the world's southernmost capital city.
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.
Another equinox fun fact: On Saturday, the sun rises almost due east and sets nearly due west for most of the world, except at the North and South Poles.
Although some people say 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 Monday, meteorologists and climatologists say summer ended Aug. 31, the final day of the three hottest months of the year (June, July and August).
According to the National Oceanic and Atmospheric Administration, the summer of 2019 (June through August) was the warmest on record for the Northern Hemisphere.
So, when do we turn the clocks back?
While the first day of fall is Sept. 23, we won't turn the clocks back until Nov. 3, 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.
This article originally appeared on USA TODAY: First day of fall 2019: Autumnal equinox is Sept. 23