Understanding GMT Watches: Dual Time Zone Timepieces by Extropian
What is a GMT watch we hear you ask? Well, to put it simply, a GMT watch is a timepiece that allows you to tell the time in two different time zones - sometimes more - both a 24-hour and a 12-hour timescale, making it one of the most useful watch types out there. It also has to be one of the coolest with its origins in the ultra glamorous world of 1950s and 60s air travel. However not all GMT watches are created equal! There’s a world of difference between the “True”, or Travelers, GMT and the Office GMT. Both can be super useful, depending on your needs. And both options are really stylish too! Let’s have a quick look at the origins of this wonderful creation, the different types and how they work!
GMT watch explained
Time for a little history lesson - with a bit of geography and math thrown in. Don’t worry, there won’t be an exam at the end!
Back when humans first began to travel long distances overseas they realized it would be kinda important to track their progress on maps. You know those horizontal lines you see on globes? Well, those are known as lines of latitude which are distributed around the Earth using the equator as their origin. Ship crews measured this using a sextant, a device that calculated the angle of the stars to the horizon. However, knowing only the latitude wasn’t much help when it came to plotting ships on a map. For that you also needed vertical lines, known as longitude, and that’s where GMT comes in.
It was decided that the 0 degree vertical line should run through the Royal Observatory in Greenwich, London. This line is called the Prime Meridian and theoretically it is noon when the sun reaches its highest point directly above it. The only snag is that the Earth’s elliptical orbit and tilted axis means that ‘noon’ is a few minutes out of sync every day. To solve this little problem, an annual average - or mean - was calculated. In 1884 an international convention agreed that Greenwich’s “mean time” would be the one against which the rest of the world’s time zones would be compared.
With a timepiece displaying GMT it was possible to determine the longitude by observing the position of the sun at noon and calculating the difference between local and GMT time. Of course back then the fastest travel option was by boat so it wasn’t hugely relevant to the population at large! But then came airplanes.
The origins of the GMT watch
With the advent of air travel it was suddenly possible for people to cross multiple time zones in hours! Pilots flying long routes needed to know the time locally and back home. The iconic airline Pan Am, the epitome of cool back then, approached the equally iconic Rolex and asked them to create a watch that could serve this ultra contemporary need.
Never a brand to disappoint, in 1954 Rolex launched the GMT-Master, the first timepiece to track two time zones simultaneously. The connection with pilots - then possibly the coolest profession imaginable - meant that GMT watches were hip from the outset!
The modern GMT watch
Somewhat ironically, only a year after the invention of the GMT watch Coordinated Universal Time (UTC) was invented to replace GMT. OK, it is more accurate, but thankfully those who have the power to decide on such things stuck with the GMT scale to avoid major confusion and disruption to timezones, so the term GMT is still commonly used. Let’s face it, ‘UTC watch’ just doesn’t sound so good!
Nowadays you don’t have to be a pilot to want or need a GMT watch! For business people keeping in touch with their foreign clients, to academics and medics attending conferences abroad - all manner of professions can make use of one. And now that so many of us are working from home with clients and colleagues across the world it’s super practical to be aware of time differences! It’s even useful for those who just want to make sure they’re calling a friend abroad at a convenient time - the GMT watch really is for everyone!
How does a GMT watch work?
The GMT’s defining characteristic is the addition of a 4th hand, also known as the GMT hand, alongside the hour, minute and second hands. This is usually a different shape and size to stand out from the other three, and watch designers often go all out to create funky designs with this feature! A GMT watch will also feature a 24 hour scale that can be a rotating bezel, an internal scale on the chapter ring or on the dial or it can sometimes be more original. However other functions will depend on the type of GMT watch you have.
Aquadive Bathysphere - Diver GMT (Diver bezel + 24H internal markers)
❤️At Extropian, we love the combination of retro inspired features with contemporary quality standards in this model!
Boldr Odyssey Freediver GMT (24H GMT bezel)
❤️ It’s the bold, chunky design of this one that Extropian adores!
Detroit Watch Co 1701 Pontchartrain GMT Dual Time Zone (Internal GMT 24H and internal regular 12H markers)
❤️ The elegance of this little beauty has it at the top of Extropian’s wishlist!
Dufrane GMT Watch (24H GMT bezel + regular internal 12H markers)
❤️ We love the fun, poppy aesthetics of this cool micro-brand watch.
Isotope GMT 0º (bespoke inner circular GMT wheel)
❤️ Extropian loves an innovator and here we have just that with the totally unique combination of a date dot and GMT disc!
The different types of GMT watch
As we mentioned before there are two different types of GMT watch. The “True” or Travelers GMT watch is, as the name suggests, great for travelers while the Office GMT is better suited for those who prefer to stay closer to home. Let’s have a look at the differences.
The “True” or Travel GMT watch
On a “True” or Traveler’s GMT, the main 12-hour hand can be jumped forward or backward in 1-hour increments, usually via the crown pulled out one click. With this type of GMT watch you can quickly and conveniently set the watch to your new local time with a few turns of the crown - all without disturbing the timekeeping of your home time zone! These movements also adjust the date in either direction when the local time crosses midnight, meaning that you don’t have to perform a separate task when crossing over midnight.
Norqain Adventure Neverest GMT 41mm - “True” GMT
❤️At Extropian, we are totally crushing on this stylish, rugged model which comes with a choice of stainless steel bracelet, a flex fabric strap or a rubber NATO strap.
How do I use a True or Travel GMT watch?
With a Travel or “True” GMT watch you pull the crown to 2nd position and adjust the 24 hour hand to reflect whatever time zone you have just landed in. Your home time zone will remain the same!
The Office GMT watch
As the nickname suggests, these watches tend to be more convenient for wearers that stay in one place. They look the same from the dial side but the operation of adjusting the time is quite different from a True GMT. On the office GMT, the 24-hour hand is the one that is jumped in one-hour increments. Typically, the 24-hour hand can only be adjusted forward, but this means that these movements retain the ability to quickset the date by turning the crown in the other direction.
RZE Ascentus GMT - Office GMT
❤️A case and bracelet made with surface hardened titanium, Seiko’s new mechanical GMT movement and a great price. We have a crush!
How do I use an Office GMT watch?
To set the watch to your local time you pull out the crown to the furthest position, set the hour and minute hands, push the crown back to 2nd position and then adjust the 24 hour hand to reflect your chosen 2nd time zone. Clearly this is not so great if you want to travel as you would have to adjust all the hands at one time!
What if I want to display multiple time zones?
Once upon a time the answer would have been - you need a World Timer! This incredible timepiece features an internal bezel displaying 24 world cities, each representing a different time zone. Next to this is a 24-hour ring, or hand, that makes one full revolution a day. To use it you set the time-zone bezel to align to your home time zone with the correct hour of the day on the 24-hour ring. As time passes, the 24-hour ring or hand rotates. The point where the 24-hour ring lines up with the time zone you’re looking for shows you the hour of the day. As you might expect, the level of complexity involved in such craftsmanship comes with a pretty hefty price tag!
But don’t fear, if you need a watch displaying multiple time zones - maybe you’re a super successful type with clients all over the world, maybe you just like to keep track of these things, who knows! - some brands have managed to create a version of the World Timer using a GMT based caliber, which is a little more affordable. This type of watch can show different time zones on a bezel, however what it won’t have is the rotating location ring. Despite the differences, more and more of these GMT watches are being described as World Timers. Just so you know!
Zodiac Super Sea Wolf World Time
❤️At Extropian we love the combination of a traditional GMT tracker with a World Timer outer ring and bezel indicating 24 global cities in this model.
Conclusion
Now you know all about the GMT watch - the fact that it’s useful and incredibly cool - you have to have one, right? Shall we have a look at some of our other favorite models that we’re pretty sure you’re going to like too?!
Models you might like
❤️ Extropian loves the sporty aesthetics of this one!
❤️We adore the combination of a GMT function with a 30 ATM water resistance rating in this model.
❤️ Extropian is totally crushing on the gorgeous ruby red face of this little beauty!
❤️ Extropian loves the ability to track a third time zone that comes with this model.
A little extra : the evolution of GMT watch design
As with many technological innovations, the design and aesthetic of the GMT watch have evolved considerably since its inception. Initially crafted with the primary goal of functionality, the GMT watch soon started drawing attention from watch aficionados for its unique design features, and brands began to recognize the potential of merging form with function.
The 1970s and 80s saw a shift in GMT watch designs, incorporating more modern aesthetics, brighter color schemes, and introducing innovative materials. With the emergence of digital technology, a few brands even experimented with blending analog and digital displays, providing both the classic feel and the precision of modern technology.
By the turn of the millennium, luxury watchmakers started producing limited-edition GMT watches, emphasizing intricate craftsmanship and using premium materials like sapphire crystals and high-grade leather. These watches weren't just tools for travelers anymore; they had become statements of style and sophistication.
Today, the GMT watch market is diverse, catering to a broad spectrum of users. From rugged designs aimed at adventurers to sleek, minimalist styles for the corporate world, there's a GMT watch for every wrist. Innovative features, such as solar charging and smart connectivity, are now being integrated, making these timepieces more versatile than ever.
As we journey further into the 21st century, the GMT watch will undoubtedly continue its legacy, combining rich history with contemporary design, proving that some inventions truly stand the test of time.
Created the 2022-12-08
Modified the 2023-11-30