Based on Coordinated Universal Time (UTC), the standard time commonly used is adopted by countries and regions around the world.
Standard time is determined by nations and regions, with “time zone” used to refer to the whole of a region that uses the same standard time. At present, the globe is divided into 38 time zones (as of January 2019).
DST (Daylight Saving Time)
Depending on the area, DST (Daylight Saving Time) is individually set.
Daylight Saving Time means summer time, which is a system to lengthen daylight time by advancing 1 hour when daylight time is long in summer.
Daylight saving time has been adopted in about 80 countries, mainly in Europe and North America. The adoption and duration of daylight saving time vary depending on the country.
DST (daylight saving time or “summer time”) in each region may be changed by countries and regions.
Coordinated Universal Time (UTC)
UTC is the universal standard time coordinated through an international agreement. This is used as the official time for recording time around the world. The time obtained by adding a leap second to the “International Atomic Time (TAI)” determined based on the atomic clock around the world and coordinated in order to compensate for deviations from universal time (UT) which is astronomically determined is the UTC.