The Swiss time change this Sunday is based upon the European Summer Time. The variations of standard clock time is an interesting point, that passes by us this time every year. Did you know that this change is applied in most European countries, apart from countries such as Iceland, Georgia, Azerbaijan, Belarus, Turkey, and Russia that do not change? This period between spring and autumn, during which clocks are advanced by one hour from the time observed in the rest of the year, this is to make the most efficient use of seasonal daylight.
European Union Directive 2000/84/EC makes the observance of summer time mandatory for EU member states (except overseas territories), though a proposal to repeal this directive and require that member states observe their own choice of either summer or winter time year-round from 2021 is currently going through the legislative process as of March 2019 (wiki).
Further information: http://www.webexhibits.org/daylightsaving/c.html
Have a great day!
SWISS UMEF University PR & Communications team