Time+Zones

=Time Zones=

The world's time zones are based on Meridians of Longitude. There are 24 hours in a day, and 24 time zones. Each Zone is 15 degrees wide, which is the distance the sun appears to travel each hour.

As the earth is rotating on its axis in an easterly direction, time zones to your east are ahead of you. It is later in the day to the east, until you reach the International Date Line at 180 degrees. To your west, time is behind you. It is earlier in the day

To work out the local standard time, you add one hour for each time zone crossed to the east or subtract one hour for each time zone crossed to the west.

Some countries also have daylight savings, where clocks are usually advanced an hour in the summer months to make more use of the daylight hours.

When crossing the 180 degrees meridian the day changes. If you travel in an easterly direction across the International Date Line, the date goes back. You gain a day. If you travel in a westerly direction across it, you lose a day, the date goes forward.