Autumn is one of the four temperate seasons. Autumn marks the transition from summer into winter usually in September (Northern Hemisphere) or March (Southern Hemisphere) when the arrival of night becomes noticeably earlier.
In North America, autumn is usually considered to start with the September equinox. In traditional East Asian solar term, autumn starts on or around 8 August and ends on about 7 November. In Ireland, the autumn months according to the national meteorological service, Met Éireann, are September, October and November. However, according to the Irish Calendar which is based on ancient Celtic traditions, autumn lasts throughout the months of August, September, and October, or possibly a few days later, depending on tradition. In Australia, autumn officially begins on 1 March and ends 31 May.
Source: en.wikipedia.org/wiki/Autumn – 18.10.2008
A landscape can not be more calm.