20181222 Northern lights (Nordlichter)

The beginning of winter coincides with the winter solstice, which in Europe falls every year on the 21st or 22nd of December. However, meteorologists see it differently.

Winter beginning 2018: date and time

This year, winter begins in the northern hemisphere, that is, among other things in Germany and all other European countries, on December 21, 2018 at 23:22 Central European Time (CET). Here, this event also marks the shortest day and the longest night of 2018.

At this time, the zenith of the sun reaches the southern tropic, the southernmost point of the year. 

The tropic is located at 23 ° 26 ’south latitude, so he travels for example through Australia and Namibia.

December 21, December 22 – or December 1 (?)

The date of the solstice in December changes from year to year, and it depends on the time zone. 

In Germany, Austria and Switzerland, the winter solstice always takes place on 21 or 22 December.

 This applies at least for the next decades – towards the end of the century there are also winter solstices in this time zone on 20 December.

Meteorological winter beginning 2018

In meteorology, however, the seasons begin on the first day of the month in which the respective solstice or equinox falls. According to this definition, winter in the northern hemisphere begins every year on December 1st.

Meteorologists use this definition to generate four seasons of constant length to ensure statistical comparability of weather records and climate data over extended periods of time.

Shortest day 2018 – day length

The further the sun’s orbit moves south, the shorter the days in the northern hemisphere. The solstice in December marks the shortest day and the longest night of the year.
The difference between the length of the shortest and the longest day is the greater the farther one moves away from the equator. In Berlin, on the shortest day between sunrise and sunset, for example, about 7 hours and 39 minutes pass. 

The longest day of the year is 9 hours in the German capital and 11 minutes longer: it lasts 16 hours and 50 minutes.

Within the Arctic Circle, the difference is the most extreme. At the poles, the sun does not rise in the winter for half a year, in the summer the midnight sun is in the night sky, so it will not be dark for six months.
Winter beginning in June

In the southern hemisphere the summer begins with the solstice in December. The beginning of winter, however, falls on the solstice in June.
In winter the days get longer

Winter stands for cold and dark. However, as the season begins with the shortest day, the days in winter become gradually longer, not shorter (see daylight chart).

Nevertheless, winter is the coldest season. Responsible for the cooling of the earth’s atmosphere is the fact that in the winter months more heat is emitted into space than reaches us through the sunlight. 

The days are getting longer, but the solar energy is not enough to compensate for the heat loss. Only in late winter and spring, so the spring equinox, this is again the case – then the temperatures rise.

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