The world is divided into 24 time zones, each of which is approximately 15 degrees longitude wide. Time zones are based on the Coordinated Universal Time (UTC) standard, which is the primary time standard by which the world regulates clocks and time. UTC is based on the mean solar time at the Greenwich Royal Observatory in Greenwich, England.
The 24 time zones are named after their offset from UTC, which is expressed as a positive or negative number of hours. For example, the time zone in New York City is UTC-5, which means that it is five hours behind UTC. The time zone in Tokyo is UTC+9, which means that it is nine hours ahead of UTC.
World Time Zone
Here is a table of the 24 time zones and their offsets from UTC:
| Time Zone | Offset from UTC |
|---|---|
| UTC-12 | -12 hours |
| UTC-11 | -11 hours |
| UTC-10 | -10 hours |
| UTC-9 | -9 hours |
| UTC-8 | -8 hours |
| UTC-7 | -7 hours |
| UTC-6 | -6 hours |
| UTC-5 | -5 hours |
| UTC-4 | -4 hours |
| UTC-3:30 | -3.5 hours |
| UTC-3 | -3 hours |
| UTC-2 | -2 hours |
| UTC-1 | -1 hour |
| UTC | 0 hours |
| UTC+1 | +1 hour |
| UTC+2 | +2 hours |
| UTC+3 | +3 hours |
| UTC+3:30 | +3.5 hours |
| UTC+4 | +4 hours |
| UTC+4:30 | +4.5 hours |
| UTC+5 | +5 hours |
| UTC+5:30 | +5.5 hours |
| UTC+6 | +6 hours |
| UTC+7 | +7 hours |
| UTC+8 | +8 hours |
| UTC+9 | +9 hours |
| UTC+9:30 | +9.5 hours |
| UTC+10 | +10 hours |
| UTC+11 | +11 hours |
| UTC+12 | +12 hours |
Daylight Saving Time (DST)
Daylight Saving Time (DST) is widely used in Europe, North America, and some parts of Africa, Australia, and South America. It helps to make the daylight duration longer in summer by setting the clock 1 hour forward in the spring (start of DST period) and setting them 1 hour backward in autumn when the DST period is over.