The September or autumnal equinox occurs today, September 23. Complemented by cooler temperatures and falling leaves, the September equinox marks the beginning of the fall season for the Northern Hemisphere as days will grow shorter than nights, IPN reports.

The September equinox is the moment when the Sun appears to cross the celestial equator, heading southward. Because of differences between the calendar year and the tropical year, the September equinox may occur from September 21 to 24.

At the equinox, the Sun as viewed from the equator rises due east and sets due west. Before the Southward equinox, the Sun rises and sets more northerly, and afterwards, it rises and sets more southerly.

The equinox may be taken to mark the end of astronomical summer and the beginning of astronomical autumn (autumnal equinox) in the Northern Hemisphere, while marking the end of astronomical winter and the start of astronomical spring (vernal equinox).

According to popular tradition, if it is warm and dry today, the rest of autumn will be similar and winter will come late. If the morning of September 23 is rainy, spring will be rainy, while sunny weather in the midday means a good year. They use to peel walnuts and to gather the apples and quinces on the autumnal equinox day. Farmers prepare the first young wine from fresh grapes.