The days may be getting shorter and temperatures may be dropping slightly, but it's still technically summer until 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.
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 equinox can be pinpointed to an exact time on Tuesday, September 22. At 9:31 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 December 21.