Astronomical Fall begins with the autumnal equinox

Astronomical Fall begins with the autumnal equinox

The autumnal equinox will happen at 8:05 p.m. ET, marking the start of astronomical fall in the Northern Hemisphere, including the U.S. Across most of the Lower 48, fall marks the beginning of progressively cooler temperatures as the country begins to angle away from the Sun and daylight begins to get shorter. The equinox occurs when the sun's center crosses the Earth's equator, marking nearly 12 hours of daylight and 12 hours of night across the globe.