The astronomical seasons are different from meteorological seasons, which began on September 1. The fall equinox, also known as the autumnal equinox, is the moment the center of the sun crosses the plane of Earth's equator. This is different from meteorological seasons, which are divided into three-month periods based on the annual temperature cycle. Meteorological fall is considered to have started on September 1 and runs through November 30, which more closely aligns with the expected seasonal weather. The fall equinox marks the beginning of the shift towards winter, as the amount of darkness in the Northern Hemisphere begins to outweigh the daylight.