What You Should Know About the 2024 Fall Equinox

The days may be getting shorter and temperatures may be dropping slightly, but it’s still technically summer until Sunday, September 22. That date marks the fall equinox, or the official start of autumn in the Northern Hemisphere. Here’s everything you need to know about the yearly event.

1. When is the first day of fall?
2. What is the fall equinox?
3. When to Experience the Fall Equinox

When is the first day of fall?

The autumn equinox dictates the start of fall—astronomically speaking, that is. Meteorological fall, on the other hand, actually kicks off on September 1 each year. Meteorological seasons are a bit more consistent than their astronomical counterparts, which vary a little each year due to the sun’s position relative to Earth. Consistent seasons make it easier for weather forecasters to predict annual weather patterns. As such, meteorological fall will always begin on September 1 and end on November 30, whereas the date of the autumn equinox will vary (though it usually occurs sometime around September 22).

What is the fall equinox?

According to The Old Farmer’s Almanac, equinox comes from the Latin words aequus, meaning “equal,” and nox, meaning “night.” The word describes the times of year when the number of daylight and nighttime hours in a 24-hour period are roughly equal around the world. This happens only twice a year: during the spring or vernal equinox in March and the fall equinox in September.

During an equinox, the sun shines on Earth’s equator, distributing light fairly evenly from pole to pole. The brunt of the sun’s rays hardly ever fall on the exact center of the globe thanks to the tilt of the planet, and when they do, day and night aren’t split into even 12-hour segments. If you count sunrise as starting as soon as the edge of the sun’s disc appears over the horizon, then daytime actually lasts a few minutes longer than 12 hours on the fall equinox.

When to Experience the Fall Equinox

The 2024 fall equinox can be pinpointed to an exact time on Sunday, September 22. At 8:44 a.m. EDT, the center of the sun will line up perfectly with the Earth’s equator. Unless you live on the equator, where the sun will be directly over head and shadows will disappear, there isn’t much to notice when this moment passes. Enjoying sunset while daylight hours are still fairly long is one way to mark the occasion. After September 22, nights will become longer until the winter solstice on Saturday, December 21.

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A version of this story originally ran in 2020; it has been updated for 2024.