What Is a GMT Watch? Everything You Need To Know

If you travel often, work with people all over the world, or just want a watch with useful functionality, then a GMT watch may be just what you are looking for. GMT watches are sometimes confused with dual-time zone watches, but the GMT watch functions a little differently, which is simply due to the hand that allows you to track a number of time zones quickly. This guide will help you understand what GMT means, how GMT watches function, and why GMT watches are increasingly popular among collectors, pilots, and international travelers.

What Is The Meaning of GMT?

GMT stands for Greenwich Mean Time, which as the name implies, is the time standard that originated from the Royal Observatory in Greenwich, London. Before time zones began to emerge, people originally used solar time based on their location, which caused no end of confusion. The biggest issues came from railroad and nautical maps not being aligned in the way they determined time. Starting in 1884, GMT became the officially recognized standard time for the world, though in 1972 Coordinated Universal Time (UTC) took over as the main standard time for scientific purposes. You will still see people using GMT as the term for a time zone watch.

How Do GMT Watches Work?

The GMT watch surged in popularity in the 1950s when Pan Am Airlines requested Rolex to build a watch for pilots who were traveling through different time zones. Taking the request to heart, Rolex came up with the now famous GMT-Master nicknamed "Pepsi" because of its red and blue bezel. So what are some things that make a GMT watch so special? Well, there is an extra fourth hand, often in distinct colors, and it looks like an arrow, and a 24 Hour scale, either on the dial or on the rotating bezel. The extra hand makes one full revolution every 24 hours and is used to track a second time zone. In modern versions, you can usually set that GMT hand independently from the hour hand, allowing even more options for tracking, including a third time zone.

GMT vs. Dual Time Watches: What’s the Difference?

Although at first glance they seem to serve similar purposes, it's worth noting the difference between a GMT watch and a dual time watch. A GMT watch will use a 24 hour scale to track day vs. night in another time zone. A dual time watch will add either a second 12 hour dial or subdial, and you will lose the advantage of dual time tracking without the 24 hour indicator, leaving you wondering whether it is 3AM or 3PM in that second time zone. Using the bezel, some GMT watches link the GMT hand to the local hour hand allowing them both to rotate together. Then you can simply rotate the bezel to track a second time zone. Others allow you to set the GMT hand independently from the hour hand for even more options. Most bezels are designed to rotate freely in both directions, making it easy to keep track of both time zones. However, not all GMT watches have bezels: some GMT watches, for example, the Omega Seamaster Aqua Terra GMT, have the 24 hour scale directly printed on the dial.

Reading and Setting a GMT Watch

If the GMT hand is fixed:

1. Line the 12 o’clock marker up with the bezel.
2. Set your GMT hand to an alternate 2nd time zone. 
3. If you want to track a third time zone, rotate the bezel to offset for the correct number of hours.

If the GMT hand is independent (as on the Rolex GMT-Master II):

1. Set your GMT hand to your home time.
2. Set your local hour hand to your current location.
3. If you want to track a third time zone, simply rotate the bezel using the GMT hand as fixed.

Can you use a GMT watch to track three time zones?

Only if the bezel rotates. If the bezel is stationary, or the GMT is on the dial. It won’t do 3 time zones. It can only do two, like Rolex Explorer 2 and, sky dweller both only keep time in two zones.

Here is how you can do it:

1. Set your hour hand to local time.
2. Set your GMT hand to GMT or your home time.
3. Set the rotating bezel to track a third time zone by rotating it forward or backward (depending). Just note that if you want to check the second time zone again, you are going to have to turn the bezel back to its original position.

Can I Use a GMT Watch as a Compass?

Yes. Unlikely, but yes. Only if you're walking in the Northern Hemisphere. Just point the GMT hand at the sun, and the 12 o'clock marker on the bezel will point to north roughly, and conversely in the Southern Hemisphere. Point the GMT hand at the sun and the 12 o'clock marker should point south.

Who Uses a GMT Watch?

Basically, if your agenda crosses time zones, a GMT watch offers practicality and style. That said, GMT watches are very functional for multiple occupations including: Pilots and airline employees, Military and government employees, Business professionals with international clients, and of course, watch enthusiasts and collectors. Anyone with family or friends in other time zones.

What Are Well Known GMT Watches?

There are many historical examples of watches featuring GMT functions as well. A few examples:

• Rolex GMT-Master II (Nickname: Rootbeer)
• Tudor Black Bay GMT (Nickname: Pepsi)
• Omega Seamaster Aqua Terra GMT (James Bond)
• Rolex Sky-Dweller
• Grand Seiko Heritage Spring Drive GMT
• Oris Aquis GMT
• Patek Breitling Navitimer

Why Choose a GMT Watch?

GMT watches are a blend of a functional stopwatch, historical integration, and mechanical artistry in one stylish package! Whether you are jetting off to remote islands routinely, booking international meetings, or simply wanting a functional piece of mechanics, a GMT links you to the actual global time.

One last thought: Don't confuse a dual time watch with a true GMT watch. If the watch lacks a 24 hour hand and an obvious AM/PM marker, you are possibly not getting an authentic GMT function. If you are ready to find your best fit GMT, please check for new releases on our website as we carry the newest luxury timepieces, and offer the option of certified pre-owned watches as well.