autumn

Autumn, also known as fall in North American English, is one of the four temperate seasons on Earth. Outside the tropics, autumn marks the transition from summer to winter, beginning in September or March. Autumn is the season when the duration of daytime becomes noticeably shorter and the temperature cools considerably. Day length decreases and night length increases as the season progresses until the winter solstice in December and June. One of its main features in temperate climates is the striking change in colour of the leaves of deciduous trees as they prepare to shed.