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tradition says that the shortest night of the year is St. John , held the June 24 . However, this is a mistake, since in reality this phenomenon happens to coincide with the summer solstice , which is given in a bow from 20 to 22 June . What, then, why not make it match ?

The answer has to do with the essence of each celebration, in addition to with a calendar change. As is well known, the night of San Juan , which is held in the early morning of June 24 to remember the birth of St John the Baptist , is one of the festivities and rituals surrounding the summer solstice. A long time ago yes it did match somehow these dates, as in the old julian calendar solstice could fall on the 23rd, 24th or even the 25th of June . However, with the correction in the gregorian calendar (the currently used), the start of the summer was ahead of a few days, which led to the origin of the confusion.

Even so, the festivity of San Juan is associated with the celebrations in which they celebrated the solstice and consisted of light a fire to “give more strength to the Sun” , that from that day there will be more “weak”. And is that, although it seems contradictory, from the solstice, in the middle of summer, the days will shorten and the fall will be moving ground, until the next 21 September.

The margin of the calendars, the solstice occurs when the center of the Sun, seen from Earth, reaches its maximum declination North (+23º 27′). At that point, the maximum height of the Sun at midday is barely change for several days, and to this circumstance it is called solstice (“Sun stand still”) of summer . This is also the time that summer begins in the northern hemisphere and winter in the south.