Summer

Summer is the warmest of the four seasons in the temperate and arctic climate. Depending on whether he was there on the northern or southern hemisphere, one speaks of the northern or southern hemisphere summer. The northern summer takes place simultaneously with the southern winter.

Formation

The seasons occur because the Earth's rotation does not take place in the plane of orbit around the sun, but at 23.4 ° inclined (see obliquity ). This lie north and south poles alternately half a year in grazing sunlight, and the zenith angle of the sun changes in the annual cycle between the northern and southern tropic.

Duration

Astronomical summer begins with the summer solstice - the time at which the sun is directly above the Tropic of its own hemisphere and the days are the longest. The beginning of summer is

• On the northern hemisphere on 20, 21 or June 22, or
• In the southern hemisphere on 21 or 22 December.

After that, the days get shorter and the nights get longer. The summer ends with the autumnal equinox on 22 or 23 September in the north and on 20 March or on the night of March 21 in the south.

Since the orbit of the earth around the sun is slightly elliptical, ie deviates from an exact circular path around 1.7%, the four seasons are not exactly the same length. The northern summer is slightly longer and milder than the austral summer, because during the northern summer, the earth is a little further away from the Sun ( aphelion on July 5 ) and its direction toward the Sun changes slightly slower.

The phenological beginning of summer may differ from the astronomical considerably and is adjacent to the land-sea distribution ( maritime vs.. Continental climate ) influenced by initial weather situations and many regional factors. A further distinction between early summer, mid-summer and late summer. In glacial regions ablation crucial depends on when ( usually in September ) the first snow falls.

Meteorologically assigned to the Northern summer months of June, July and August, the southern summer the months of December, January and February. At the geographic poles there for half a year the so-called polar day, in the Arctic regions weeks of midnight sun and White Nights.

Culture

In many cultures, customs and rites with the beginning of the summer are connected, in Germany for example, the solstice or bonfires. Otherwise, the summer is also regarded as the season of increased vitality. This is attributed to particularly caused by the higher temperatures stays outdoors and released by the sun's rays hormones.