Autumn is one of four seasons in temperate climates, and is a period of transition from summer to winter.
In the temperate zones of the earth, autumn is a harvest season for plants planted or springing in spring, and the trees thoroughly shed their leaves (so-called autumn or fall). Autumn usually begins after the equinox with the movement of the sun leaving the zone. The length of the day becomes shorter and the temperature starts to decline. This season is also marked by increasing precipitation.
In the northern hemisphere, autumn calendars / astronomy takes place from September 23 (equinox to south) to 21 December, while in the southern hemisphere the autumn begins on March 21 (equinox to the north) and ends on 21 June. From a meteorological point of view, the fall begins on September 1 and ends November 30 for the northern hemisphere, while for the southern hemisphere begins March 1 and ends May 31. Other dating systems have different initial criteria, for example the Irish calendar that follows the Cycles round counts the months of August, September, and October as fall.
Although the days begin to shorten in July or August in the northern hemisphere and in January and February in the south, usually in September or March the sun goes down early.