Autumn, interchangeably known as fall in North America, is one of the four temperate seasons. Fall marks the transition from summer into winter when the arrival of night becomes noticeably earlier and the temperature cools considerably. One of its main features is the shedding of leaves from deciduous trees.
However, according to the Irish Calendar, which is based on ancient Gaelic traditions, autumn lasts throughout the months of August, September and October, or possibly a few days later, depending on tradition. In Australia and New Zealand, autumn officially begins on 1 March and ends on 31 May.