GMT History & Function | Schwanke-Kasten Jewelers

TAG Heuer Calibre 1 GMT
This year at Baselworld, it was the year of the GMT, stemming mostly from announcements from Grand Seiko Tudor and Breitling. However, you may not know exactly what this function is for or even how to set it!

A GMT, or Greenwich Mean Time, function allows the wearer to read a second time zone. Historically, GMT was used as the international civil time standard at the Royal Observatory (in Greenwich, London). As Great Britain grew into a maritime empire, sailors kept at least one chronometer aboard to measure the distance from their perceived longitudinal Greenwich Meridian which help keep track of how far or behind time they were based on a lunar calendar. The GMT then was adopted by the Railway Clearing House to sync train times. Despite being replaced by UTC (Universal Time Coordinated) time as early as the 1950’s, the GMT name stuck. Sort of like NATO straps.

In the 50’s, the jet age came around. Marked by passengers traveling long distances in a matter of hours, globetrotters began to experience a new phenomenon, jet lag. One solution developed by pilots to combat this newfound fatigue, would be to acclimate yourself prior to traveling to the destination’s time zone. 

So, without further ado, Schwanke-Kasten will answer some of FAQ’s about GMT’s

Breitling Navitimer GMT
How can you tell if your watch has a GMT function?

These watches always displayed have a 4th hand that reads off 24-hour time and is frequently accompanied by a 24-hour bezel to distinguish AM & PM.

So how are they used today? As mentioned before, when traveling setting the GMT to the destination ahead of time may help acclimate yourself to the new time-zone. Otherwise, if you are one to travel frequently, leaving the GMT on your home time serves as a nice reminder to check-in back home. In fact, many watches allow the wearer to set the GMT hand independently from the local time.

If you have a bi-directional 24-hour bezel, you can actually read off a third time-zone instantaneously.

If you are an adventure junkie, there is actually a way, explained here, to use the GMT function as a compass.

What is the best way to set a GMT? Here’s the Schwanke-Kasten preferred way.

  1. We recommend first setting the local and GMT time to midnight
  2. Then set the date
  3. Then set the local time
  4. Then set the GMT or 2nd time zone

Stop by Schwanke-Kasten Jewelers today to see our full range of GMT watches from top brands like Breitling, Tudor and Grand Seiko!