Tonight we sleep an hour less
By moving the clock indicators for 60 minutes before tonight (Sunday, March 29) at 2 am summer time starts calculation.
Calculation summer time begins the last Sunday of March, when the clock moved forward indicators at two o'clock three. While winter time calculation also takes the last Sunday of October, when the clock indicators moved by two at a time.
Such measurement of time - summer from last Sunday in March, and winter from last Sunday of October in Western Europe is set from 1970, on the grounds that by "extended" so the day is made possible savings in electricity, increasing productivity, improves the adaptation of people and working day becomes more efficient.
Shifting hour indicators front or back becomes night between Saturday and Sunday from causing confusion for employees on working days.
Passing the summer calculation for the first time came in 1916 in the countries of northern Europe, and now applies to about 70 countries mainly northern hemisphere.
In the southern hemisphere the beginning and end of summer time is opposite to that of the northern hemisphere.
Most modern operating systems have calculator to adjust automatically switch to summer time calculation and vice versa, in winter.
Some scientists oppose the movement of indicators hour front or back and "extension" artificial daylight, even from economic reasons.