Know the central reference point for all time zones is located at the Prime Meridian and is known as Coordinated Universal Time (UTC). This point is constantly monitored by the International Bureau of Weights and Measures, and the exact hour is kept with six different clocks to make sure the rest of the world is always on time.
To figure out time zones east of the Prime Meridian, one hour is added to the UTC time for each of 12 time zones until just before Hawaii in the Pacific Ocean.
To figure out time zones west of the Prime Meridian, one hour is taken away from the UTC time for each of 11 time zones until just past Hawaii.
Calculate the difference of a time zone other than the one you are in by using an online calculator or by looking at a time zone map and counting the hours (see Resources).
Memorize the time differences for any place important to you. If you want to know what time it is anywhere in the world without looking at a map, memorize the time differences for the major capital cities around the world and use that information as a good guess for what time it is somewhere close by.