What is GMT time and how can you use this function on your watch?
Not every watch shows just one time – some can do much more. The GMT function allows you to track time in two, or even three time zones simultaneously, making it perfect for travelers, pilots, and people working internationally. Before you learn how it works and what the GMT time zone actually is, it's worth knowing its history – from London's Greenwich to modern watches with the most advanced mechanisms.
GMT – what does it mean? Discover the fascinating history of time from which the whole world counts
Although you don't think about where the time you see on your watch dial comes from on a daily basis, it's worth knowing that it all starts with GMT, or Greenwich Mean Time. This term refers to mean solar time on the prime meridian, which runs through the London district of Greenwich. It was this point on the map that became the baseline from which all other time zones began to be measured.
This is where the name GMT time zone came from, which for decades has been the reference point for the entire world – in shipping, aviation, and everyday life. In practice, if you hear that someone operates in GMT+2 time, it means their local time is two hours ahead of London. It's a simple system, but extremely important for synchronizing work, travel, and global communication.
It's worth knowing that GMT's history dates back to the 17th century, when the Royal Astronomical Observatory was established in Greenwich. It was there that it was determined that the meridian passing through this point would be considered "zero." Over time, the system was adopted by other countries, and in 1884, at an international conference, it was established as the official standard. Interestingly, France long opposed these arrangements, preferring its own Paris meridian – it wasn't until 1911 that it officially recognized Greenwich. Today, GMT serves mainly a historical function, as it was replaced in the 1960s by the more accurate UTC (Coordinated Universal Time), but for watch users and in everyday language, the concept of GMT is still alive. It was this concept that became an inspiration for watchmakers who began creating models that allow tracking more than one time zone.
Zeppelin Atlantic GMT 8442-3 is an elegant men's watch that values classics and functionality in a modern edition. With a navy blue dial, leather strap, and GMT complication, it's perfect both for travel and business meetings, emphasizing the style, class, and precision of German watchmaking craftsmanship.
How the GMT function works in a watch – discover how to read time in two (or even three) time zones simultaneously
The GMT function in a watch is something many consider one of the most practical mechanical complications. Its operation is simple but extremely useful. On the dial, you'll find an additional hand – often ending with a characteristic triangle-shaped arrow. This is the GMT hand, which makes a full rotation once every 24 hours, not twice like the standard hour hand. This makes it easy to distinguish whether it's day or night in the second time zone. Usually, the dial or ring (called the bezel) features a 24-hour scale that allows you to read the time in another part of the world. In practice, you can simultaneously track, for example, local time and time in the country you're from.
Some watches go a step further – they're equipped with a rotating bezel that allows reading even a third time zone. Simply turn the ring forward or backward by the appropriate number of hours, and you'll know what time it is in Tokyo or New York, for example. This solution is appreciated by both travelers and people who collaborate with partners from different parts of the world. With the GMT function, you don't have to calculate hours "in your head" or check time differences on your phone – you have everything on your wrist. Moreover, GMT time displayed this way is extremely readable and allows you to immediately orient yourself in time regardless of which part of the globe you're in.
Gerlach PZL P.50 Jastrząb GMT is a tribute to Polish aviation and technical precision, inspired by the legendary fighter from the 1930s. Equipped with an automatic movement with GMT function, it combines military character with elegance and solid craftsmanship, creating a watch ideal for history and aviation adventure enthusiasts.
True GMT or Caller GMT? Check which type of watch suits your lifestyle
Not every watch marked GMT works the same way, so it's worth knowing that there are two main types – True GMT (Flyer GMT) and Caller GMT (Office GMT). The difference between them is subtle, but significant for the user. In True GMT models, the main hour hand moves independently, allowing you to quickly adjust local time without interfering with the GMT hand, which remains set to home time. This solution was created with frequent travelers who cross different time zones in mind – it takes just a moment to adjust the watch to a new location.
On the other hand, Caller GMT works better if you don't physically change time zones but want to track time in another place – for example, when you work with international clients or have family in another country. In this type of mechanism, the GMT hand is adjusted independently, while local time remains unchanged. This makes it easy to set the appropriate time in, for example, New York, Tokyo, or Sydney, without needing to change the main clock. This is why watches of this type are often called "office" watches – ideal for people who constantly function between different time zones but don't necessarily travel. Both types have their advantages, and the choice between them depends primarily on whether you want a watch ready for travel or rather for remote contacts. Both types – True GMT and Caller GMT – can be found in our online watch store, where models await that are suited to both the traveler's lifestyle and people working remotely with partners from different parts of the world
GMT time zone in practice – how to set and use the GMT function in everyday use
Understanding how the GMT function works is one thing, but only its practical use shows how much it can make life easier. Most watches with this complication have three crown positions: the first – for everyday wear, the second – for setting the date and GMT hand, and the third – for adjusting the main time. In practice, setting is straightforward: first you set local time, and then, using the second crown position, you adjust the GMT hand to the second time zone. If the watch has a rotating bezel, you can use it to read yet another time by rotating the ring forward or backward by the appropriate number of hours.
Such a GMT time zone in a watch is a tool you'll appreciate not only during intercontinental flights. It will also be useful if you collaborate with people in other parts of the world, follow sporting events broadcast from another continent, or simply want to know what time it is where someone close to you lives. Interestingly, in many modern GMT watches, this function is not only practical but also aesthetic – the fourth hand and 24-hour scale add character to the dial. Thanks to this, a GMT watch becomes a combination of utility and timeless design that has more to offer than simply measuring time. In our store, you'll find both men's watches and women's watches with GMT function that combine time measurement precision with elegant design and practical application in everyday life.
Krzysztof Szopa
Watch Expert
An expert associated with the WestWatches.pl brand, a place that has been providing watches for every occasion for years. Thanks to many years of experience in the watchmaking and jewelry industry, he passionately shares his knowledge, offering professional advice both in the online and physical store. He specializes in selecting original watches, watch accessories, and jewelry products that combine exceptional quality with competitive prices. His goal is to help customers find the ideal product that will meet their expectations and emphasize their style.
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