Three letters, expressed by one hand. The GMT function is perhaps the easiest of all to understand. In addition to the time and date, a secondary centrally mounted hand indicates a different hour, that of the time zone of your choice. Elementary! The principle has existed for the last 80 years. The GMT Master 2 of Rolex is the archetype of this watch, but all brands have their own variations: Bell & Ross has the V2-93 GMT, Panerai has the Luminor GMT, Breitling has the Avenger GMT, Grand Seiko the Spring Drive GMT, and various others.
The Disappearance Of GMT
That said, the term GMT has no value apart from marketing. “Greenwich Mean Time” no longer exists as a timekeeping convention. It has been replaced by UTC, or Coordinated Universal Time. The two terms have exactly the same definition, but GMT, which was originally imposed when Britain was the world’s leading naval power, has officially disappeared from international standards since 1972. It’s eminently justifiable, since, in the vast majority of cases, the GMT system involves many other time zones than Greenwich!
... And The Arrival Of UTC
Some brands have therefore wisely adopted the official term "UTC". There is the IWC Aviator's Watch UTC, the Montblanc TimeWalker Chronograph UTC, etc…
Others have taken their own paths. Jaeger-LeCoultre prefers the term Universal Time, although in practice, this watch is better described as a worldtimer: a watch capable of indicating, at a glance, what time it is in a set of reference cities. They can be found at Frédérique Constant (Classic Manufacture), Ulysse Nardin (Executive Moonstruck WorldTimer), Hamilton (Khaki Chrono Worldtimer), Baume & Mercier (Capeland Worldtimer), etc…
Did You Say Dual Time?
The category of "Dual Time" watches stands apart. What’s it all about? No one has defined it precisely. If the UTC watch indicates a second time zone, if the Worldtimer indicates the time of the world's cities, can Dual Time be understood as a watch… with two completely separate dials? This is the hypothesis adopted by Armin Strom with its Dual Time Resonance, by Hamilton or with the Slim d’Hermes. These watches remain exceptions, like the Icon and QuattroValvole by Meccaniche Veloci which has four independent dials!
Best Of The Best
In practice, the majority of collectors prefer a UTC model indicating a single second time zone — those watches that watchmaking continues to call "GMT". The offering is wide, although curiously predominantly masculine. The advantage of the GMT watch is its aesthetic flexibility: a single additional hand is a minor complication that requires no modification of the dial or even the case. The GMT hand can blend in with just about any aesthetic.
In "travel" mode, the Rolex GMT Master II remains a sure bet, complemented by the Breitling Avenger Automatic GMT 45 for a more virile and adventurous declination. In "classic" mode, the Blancpain Villeret GMT Date will look right at home on the red carpet alongside a Louis Vuitton Tambour Essential GMT or the Schwarz-Etienne "Roma Manufacture GMT".
In "sport" mode, the range extends from the Eberhard Scafograf GMT diver to the Alpina Seastrong Diver GMT. On the road, you can’t go wrong with the TAG Heuer Carrera Heuer 02 GMT is preferred, alongside the Big Bang Unico GMT.