A GMT watch shows the user multiple time zones at once.
GMT stands for Greenwich Mean Time, which is the reference time defined in 1884 by the Royal Observatory in London as the zero point for time zones.
A GMT watch is equipped with an additional 24-hour hand, enabling a second time zone to be displayed. Unlike the traditional hour hand, which circles the dial in 12 hours, the GMT hand completes a full rotation in 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 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.
Longines has established itself as a preeminent expert in GMT watches. The brand created history with its famous Turkish Watches in 1908 – the first dual-time pocket watches – and secured this innovation with a patent in 1911. In 1925, Longines advanced horological history again by introducing the first dual time wristwatch, the Zulu Time, which displayed both local time and Greenwich Mean Time (UTC+0). The watch featured the signal flag for the letter “Z” – a symbol used by both sailors and aviators in international time communications. By the early 1930s, Longines had developed one of the first true GMT cockpit clocks, which became indispensable tools for aviation pioneers like Hugh Herndon and Clyde Pangborn during their historic non-stop Pacific crossing in 1931.
How to use a GMT watch
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 around the globe. Some GMT watches also display additional features, including compasses, date, moonphase or 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 fitted with 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 the hour hand (as above) 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?
When looking for the best GMT watch, it is important to choose a timepiece that combines precision, functionality and timeless style. A high-quality GMT watch should feature a clearly visible 24-hour scale, an independently adjustable local hour hand for easy time zone changes and a reliable movement for precise timekeeping. Ideal for frequent travellers and international professionals, a GMT watch offers the ability to track multiple time zones at once. LONGINES offers some of the best GMT watches, including the LONGINES SPIRIT ZULU TIME, known for its aviation heritage and chronometer-certified movement, the HYDROCONQUEST GMT, a sporty and robust option for active lifestyles, and the LONGINES MASTER COLLECTION which combines classic elegance with advanced GMT functionality.