The 2024 Autumn Equinox Is Fast Approaching: Everything You Need to Know

Summer isn’t technically over yet, but fall is just around the corner. There are specific times when the astronomical seasons officially change. In the fall, it’s the autumnal equinox. In the spring, it’s the spring equinox.

The autumn equinox in the Northern Hemisphere falls in September and marks a welcome change of seasons for many after a long, hot summer. But what exactly is the equinox? It’s all about the Earth and its relationship with the sun. Here’s how to understand, visualize, and celebrate the autumn equinox.

Understanding the Equinox

The meaning of the equinox is contained in the name itself, which is a combination of the Latin words for “equal” and “night.”

“There are only two periods each year when the Earth’s axis is tilted neither toward nor away from the sun, resulting in “nearly” equal amounts of daylight and darkness at all latitudes,” the National Weather Service says in an explanation of the seasons.

Earth spins on its axis (imagine a line running from pole to pole), and the planet has a whopping 23.5-degree tilt. This tilt is what gives us seasons. As Earth orbits the sun, the tilt means that some areas of the planet get more direct sunlight than others. That’s why it can be summer in the Northern Hemisphere (tilted toward the sun) and winter in the Southern Hemisphere (tilted away from the sun) at the same time. During the equinoxes, the sun shines directly on the equator and gives equal love to both hemispheres.

Other planets that are also tilted on their axis also experience equinoxes. The timescales can be very different, though. Saturn’s equinox occurs only about every 15 Earth years. That means each season lasts more than seven years on Saturn. Neptune is even wilder, with seasons that last decades. We can be grateful for our planet’s relatively short seasons.

When is the autumn equinox?

The autumnal equinox in the Northern Hemisphere falls on September 22 this year. If you want to be more specific and put it on your calendar, mark it for 5:44 a.m. Pacific Time. The dates of the equinox can change slightly from year to year, but it always falls around this time in September. The next spring equinox in the Northern Hemisphere will be on March 20, 2025, marking the beginning of spring.

How is the equinox different from the solstice?

Like the equinoxes, the solstices are related to the Earth’s tilt, but instead of equal day and night, the days and nights are extreme. The winter solstice is the shortest day of the year, while the summer solstice is the longest. The winter solstice in the Northern Hemisphere falls on December 21 this year.

See the equinox from space

Satellites observing Earth in orbit have a unique view of the equinox. NASA’s Earth Observatory video shows Earth from space and how the position of sunlight changes with the changing seasons. It’s a great way to visualize what happens as our planet orbits the sun.

How to Celebrate the Autumn Equinox

Equinoxes aren’t like eclipses or meteors. There’s no big wow moment when you see something spectacular. The autumnal equinox will look like any other day this year, but it’s a handy way to mark the change of seasons in astronomy. You can go out and declare, “It’s officially the first day of fall!” How you celebrate is up to you. Here’s a suggestion: throw on your favorite sweater, take a scenic drive through the leaves, and sip a pumpkin spice latte to welcome fall in style.