When is the first day of fall? All about the 2024 autumnal equinox

Labor Day, often called the " unofficial end " to summer, has ushered a new season. With it come pumpkin spice lattes and harvest decorations lining store aisles .That's right: autumn is just around the corner.

The autumnal equinox officially marks the start of fall. The word " equinox " comes from the Latin words "aequus" and "nox," which mean "equal or even" and "night," respectively. That's because there is nearly the same amount of night and day during an equinox.

So, when is the autumnal equinox in 2024? Here is what you need to know:

When is the first day of fall?

The first day of fall in 2024 is Sunday, Sept. 22.

What are the fall months?

In the Northern Hemisphere, the fall months are from the end of September, through October and November and into the first weeks of December. The winter solstice will be Saturday, Dec. 21, 2024, making late December the start of the winter months.

What is the birthstone for September? Get to know the fall month's stunning gem.

The autumnal equinox, explained

According to the National Weather Service, there are two times a year when the Earth's axis is tilted to a point where there is "nearly equal amount of daylight and darkness at all latitudes."

There are two equinoxes: The autumnal equinox marks the start of fall, while the vernal equinox marks the start of spring.

The apparent equal hours of daylight and darkness result from the refraction of sunlight , or the bending of light's rays, the National Weather Service reports. This refraction causes the Sun to appear above the horizon when it is actually below the horizon.

During the autumnal equinox, also referred to as the "September equinox," the Sun crosses the celestial equator going from north to south. In the Northern Hemisphere after the autumnal equinox, the days begin to get shorter as the winter solstice gets closer.

Fall foliage predictions: These maps show when and where to see peak colors.

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This article originally appeared on USA TODAY: When is the first day of fall? All about the 2024 autumnal equinox