As the Northern Hemisphere welcomes spring today, the Southern Hemisphere is marked with the first day of autumn.

The date and time of the equinox varies slightly from year to year. The Earth is not tilted toward or away from the sun on the first day of fall as well, also called the autumnal equinox.

Today marks the first day of spring 2025. The vernal equinox marks the start of spring every March. The autumnal equinox marks the start of fall every September. An equinox occurs, "two times of ...

On the contrary, in the Southern Hemisphere, the upcoming equinox is known as the autumnal equinox, as it represents the start of fall. During this time, the Southern Hemisphere begins to tilt ...

During this equinox, the sun will shine directly on the equator with nearly equal amounts of day and night, about 12 hours. The autumnal equinox, or start of fall, happens on Sept. 22, 2025.