The time at 45 degrees East is 12noon What is the time at the Prime Meridian?

Answer 1

Every 15 degrees of longitude represents one hour. So 45 degrees east of the Prime Meridian is ahead of UTC by 3 hours (45 divided by 15). So the absolute time at the Prime Meridian when it is 12:00 noon at 45o E, is 09:00 hrs.

However, different countries set their time zones by reference to political and practical considerations, not just by their position in relationship to lines of longitude. Consequently in some situations, the local time in at the Prime Meridian will be different from that of other countries through which the Prime Meridian runs.

For example, local (standard) time at the Prime Meridian in France and Spain and Algeria is UTC +1, whereas in the UK it is UTC +/- 0.

Similarly, standard time at 45o E is generally UTC +3, but there are exceptions: Iran, for example. Longitude 45o E passes through Iran, but it is a large country, and for convenience, has adopted UTC +3.5 as its standard time zone (Iran Standard Time/IRST). So when it is 12 noon at 45o E in Iran, it is 08:30 hrs at the Prime Meridian in England but 09:30 hrs on the Prime Meridian in France.

For more information about the Prime Meridian, see Related links below.