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Longines - What is a GMT
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What is a GMT Watch

A GMT watch shows the user two time zones at once. 

A GMT watch shows the user two time zones at once. GMT stands for Greenwich Mean Time, the time-meridian, which is the zero-hour standard according to the Royal Observatory in London. In 1884, this location was chosen as Earth’s zero degrees in longitude. GMT watches feature an additional 24-hour hand, which shows the second time zone. While the normal hour hand travels around the counter once every 12 hours, this GMT hand travels around the counter once every 24 hours. Some GMT watches feature a rotating bezel with a 24-hour scale, meaning they can show two time zones at once.

The GMT scale is in 24-hour time, making it easy for the user to tell the difference between AM and PM. The normal hour hand displays the local time, while the GMT hand shows the time in a second time zone. Users can glance at the display and view both time zones simultaneously, quickly helping them arrange meetings across the world, remain punctual and adapt to different time zones.

GMT watches date back to the 1950s, known as the golden age of flying. Read on to discover more about the history of GMT watches, how they work and how to use them.

How to use a GMT watch

GMT watches were invented for pilots in the 1950s, when the first long-haul flights were launched. As pilots were flying in different time zones, they needed a timepiece that displayed the local time of their destination and the time in the place they had departed from. Today, GMT watches aren’t just used by pilots – this timekeeping solution is perfect for frequent fliers, especially those who travel for business and those who have frequent layovers and connecting flights.

The ability to see two time zones at once saves the user from mentally calculating the time across different time zones and working out the time differences between meetings, appointments, and events in various destinations across the world. The aesthetics of GMT watches are also unrivalled. The first GMT watches were made with a red and blue rotating bezel, otherwise known as the traditional “Pepsi” bezel. This striking design brings a strong sense of power to every GMT watch. Some GMT watches also display additional features, including compasses and chronograph counters, perfect for users seeking adventure in their timepiece.

To properly read a GMT watch, identify the GMT hand. This additional hour hand is usually indicated by a small arrow. This hand is also a different colour to the other hands on the watch display for easy visibility. Use the crown to adjust the GMT hand and align it with the desired second time zone on the 24-hour scale on the rotating bezel. The normal hour hand should be set to the local time zone. To read the GMT hand, note which number it is aligned with on the 24-hour scale.

What should I look for in a GMT watch?

GMT watches are known for their additional technical features, such as compasses and chronograph counters. The Longines Spirit Zulu watches are not just GMT watches – they are certified chronometers. After a series of intense precision tests, these timepieces have proven to be accurate to the highest degree, making them a very rare type of watch. The Hydroconquest GMT watches feature a new unidirectional notched bezel, helping the user track time. The Longines Master collection shows a whole host of additional information, including a Moonphase display, small second hand at 6 o’clock and a day/night indicator at 12 o’clock.