GMT and World Time watches: Perfect accessory for today's busy life

Apr 16, 2013
GMT and World Time watches: Perfect accessory for today's busy life
GMT and World Time watches: Perfect accessory for today's busy life

Of all the functions available on a watch, one of the most useful lets the wearer know the hour in more than one time zone. A GMT or Dual Time Zone watch normally tells you the time in two time zones. World Timers are more complex, but growing in popularity. It can display the time of up to 24 time zones around the world. A World Timer differs from a GMT watch, as while a GMT has a standard hour hand and a second 24-hour hand that can be set independently, a world timer will have a home time and a display of various countries, cities or other zones, and a hand that will show the time at each.

With the increase of global business and travel, for some it's more important than ever to be aware of times around the world. Rather than doing the time zone shuffle with your watch when you travel, resetting the time when you reach your destination, traveling with a dual time zone (or GMT) watch can help sometimes prevent the need for manually adjusting the time. Today nearly every major fine watchmaker has at least one dual time zone model. GMT or Dual Time Zone models tend to show home and local times only, while the more complex World Time watches display the time in a number of locations worldwide.

GMT function

Greenwich Mean Time (GMT) is also known as Zulu Time and UTC (Universal Time Coordinated). GMT is the time standard against which all other time zones in the world are referenced. It is the same all year round and is not affected by Summer Time or Daylight Savings Time.  GMT is an absolute time reference that does not change with the seasons.

The GMT function is probably the most useful complication to have in a traveller’s watch as it allows the watch wearer to immediately read multiple time. Most GMT watches tell you the time in two time zones, your home time and the local time, though there are some which can display more than two. There is a variety of ways in which this complication can be displayed. But it is generally displayed by an additional hour hand which tracks time in a 24 hour mode. The reason for showing the additional time zone in 24 hour mode is to allow the wearer to know if the second time zone is in AM or PM. Some watches have a separate sub-dial showing the full clock at the additional Time Zone. Another approach is displaying the second time in a second window using a digital hour display. This provides a clean separation from the main hands.

In its basic form, the GMT can be added to other complications relatively easily.

World Timers

By far the most complex and evocative travel watches are the so-called world timers, which register the time in a selection of cities listed on the bezel. Louis Cottier, an independent watchmaker who worked in Carouge, Switzerland, is credited with devising the mechanism that enables this function. In addition to the easily adjustable international settings, Cottier’s watches, the first of which appeared in 1931, often featured dials handsomely decorated with images of the globe. In the 1930s and ’40s, as plane travel was becoming more convenient and more popular, Cottier sold his world-timer design to a number of companies, most notably Patek Philippe, whose collection still includes versions of these watches.

Even today most world-time indications are based on the 1931 Louis Cottier design.The World Time Zone feature has a rotating inner bezel with 24-hour display, part of the watch movement, and an outer bezel, listing the major cities in each of the 24 time zones. The outer bezel is set by the user. The inner bezel, marked to 24, makes one complete revolution per day.

With the main dial showing the home time, one gets the time in a listed city by reading off the nearest number on the 24 hour indicator disc. The names of the cities are printed on the dial. The hour in a particular zone can be read by looking at the scale next to the city that the hour hand is pointing to. The minutes are read in the normal way. The dial is usually found on the outer edge of the watch face. Due to the nature of the design, world time watches tend to have very busy dials.

Sometime manufacturers of timekeepers erroneously apply the worldtime label to instruments that merely indicate time for two or a few time zones, but the term should be used only for timepieces that indicate time for all major time zones of the globe.