Daylight saving time

Daylight saving time (DST), also referred to as daylight savings time, daylight time, or summer time, is the practice of advancing clocks to make better use of the longer daylight available during summer by having darkness fall at a later clock time. The typical implementation of DST is to adjust clocks ahead of standard time by one hour in spring or late winter, and to set clocks back by one hour in the autumn.

daylight savings time in the central European time zone

variation of standard clock time that is applied in most European countries in the period between spring and autumn when to set your clocks back an hour

changes introduced to the Soviet Union time system

Wikimedia list article

alteration to GMT by King Edward VII on his royal estate