Welcome to Autumn!

On September 22, 2025, the Northern Hemisphere experiences the autumnal equinox, marking the official arrival of fall.

Although “equinox” comes from the Latin for “equal night,” the balance between daylight and darkness isn’t exact today. Because of atmospheric refraction and the Sun’s rounded disk, we actually receive a bit more daylight—about 12 hours and 8 minutes in total. The true balance of day and night, called the “equilux,” happens a few days later, around September 25.

The fall season is here, as marked by the autumnal equinox, which will happen Monday.

The autumnal equinox will occur Monday, Sept. 22, at 12:19 p.m. MT/1:19 p.m. CT, signaling the end of summer. 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 roughly 12 hours long in most of the world.

During the autumnal equinox, the Earth’s axis is tilted neither toward nor away from the sun, resulting in a “nearly” equal amount of daylight and darkness at all latitudes, according to the National Weather Service.

Because our hemisphere is exposed to the sun’s rays less directly because of the Earth’s tilt, days will become darker and shorter as the winter months approach.