World Time Zones

Time zones are areas whith uniform standard time for commercial, legal, and social purposes. All time zones range from UTC (Coordinated Universal Time) -12:00 to UTC +14:00.

Many countries, and some regions, apply the daylight saving time, during a certain period of the year, advancing clocks by an hour near the start of spring and adjusting back in autumn in order to maximise the sunlight time during the day.
Due to the minimal difference in sunlight, equatorial countries usually do not adopt the daylight saving time.

The first idea of adopting different world time zones was from the Italian mathematician Quirico Filopanti in his book Miranda! (1858), but the official adoption was only around 1930.