Understanding the World’s Time Zones
The Earth rotates around its axis once every 24 hours. We therefore
have 24 time zones, each one hour apart. Each time zone is 15 degrees wide
because 15 degrees times 24 (hours) equals 360 degrees (a full circle).
Every place within a time zone has the same time called the standard time.
The Prime Meridian, which runs through Greenwich, England, runs
through a time zone where time is called Universal Time (UT). The
standard time zones in other parts of the world are compared to this
universal time.
Since the Earth rotates from west to east, time zones that are east of
the primer meridian have local times that are ahead of UT. Those time
zones on the west are behind.
Time zones east of P.M. = Ahead UT
(e.g. – Noon at the P.M. = 8p.m in Western Australia)
Time zones west of P.M. – Behind UT
(e.g. – Noon at the P.M. = 7a.m. in Toronto)
Countries may modify time zones and often do for reasons such as the
following;
-
convenience
political reasons
to avoid having various time zones
to avoid having time zones run through a given city