What Does GMT Mean Regarding Rolex Watches?

by Andy Jones on Dec 19, 2023

What Does GMT Mean Regarding Rolex Watches?

Have you ever encountered the mysterious three-letter code "GMT" in the name of the Rolex GMT-Master? Have you ever pondered its significance & how it affects the form & function of the watch? 

Well, prepare to have your curiosity satisfied! In this guide, we will unravel the secrets behind those three letters & dive into the fascinating world of the Greenwich Mean Time complication, shedding light on what it means for your choice of wristwatch. 

Get ready for an enlightening journey!

What Does GMT Mean?

Indeed, GMT is an abbreviation for Greenwich Mean Time, which refers to the time standard based on the location of Greenwich, a place in England. Situated in South East London, Greenwich boasts a storied maritime history, making it the ideal choice as the "prime meridian" at the International Meridian Conference held in Washington D.C. in 1884. 

It is worth noting that this decision was made 33 years after Sir George Airy had established the meridian in 1851.

Forty-one delegates from 25 countries convened to establish an official meridian for simplifying global navigation systems. Given its preexisting fame, with approximately two-thirds of all vessels recognizing Greenwich as 0° Longitude, it emerged as the clear choice. 

However, the French delegation abstained, opting to adhere to the Paris Meridian for several decades afterward. Ultimately, the Paris Meridian fell into disuse in 1914 & is now recognized as Longitude 2°20'14.03″ East about Greenwich.

The Greenwich Meridian holds a significant role in timekeeping & navigation. Time Zones across the globe are expressed relative to Greenwich Mean Time (GMT), indicating the time difference ahead or behind. For instance, Paris is typically one hour ahead of England, denoted as GMT+1 (or UTC+1, which represents Universal Time Coordinated). 

While such usage is widespread & easily understood, the meaning behind these abbreviations & their significance is not well-known to many.

What Does This Have To Do With My Rolex GMT-Master?

During the 1950s, commercial air travel experienced a significant boom, leading to an increasing number of pilots & cabin crews spending considerable time in time zones distant from their homes. Consequently, it became crucial for these pioneering aviators to meticulously track a second (or even third) timezone.

In 1955, Rolex introduced its inaugural GMT watch, developed with design input from Pan-Am crew members. This timepiece followed closely in the footsteps of the Glycine Airman, which had already been on the market since 1953, offering similar functionalities.

Like its predecessor, the Airman, the Rolex GMT-Master employs a 24-hour bezel - an outer rotating ring encircling the watch face - to monitor a secondary timezone. This is accomplished through a prominent, arrow-tipped hand that completes a full rotation of the dial every 24 hours.

The hand, the GMT hand, operates at half the speed of the regular hour hand, positioned on the central axis above it. It is important to note that GMT should not be mistaken for dual time watches, which utilize one primary display for the home time & a secondary sub-register or secondary 12-hour hand for the second time zone. 

GMT watches effectively showcase two (or three) time zones using a single dial, a conventional handset (hours, minutes, & seconds), a 24-hour (or GMT) hand, & a rotating bezel.

One Timezone, Two Or Three?

As mentioned previously, it is possible (albeit uncommon) to simultaneously utilize certain GMT calibers to display three time zones. However, this functionality is not universal across all models, nor is it straightforward for those that do possess it. 

The key lies in the independent adjustment of the GMT/24-hour hand relative to the standard hour hand. In the initial Rolex GMT-Master watches, this capability was not available. It was only with the introduction of the renowned GMT-Master II watches in the early 1980s that this feature became an option.

Let's begin with the fundamentals: a conventional watch indicates the time in a single location. It consists of a 12-hour dial and, at the very least, a minute hand, along with an hour hand that completes two full rotations within 24 hours. 

Two different times can be displayed by incorporating a GMT/24-hour hand & a rotatable 24-hour scale alongside the standard 12-hour scale on the dial. In cases where these hands are synchronized (such as in the GMT-Master), both displayed times are identical. However, one represents the time in a 24-hour format, indicating whether it is AM or PM.

Enabling the adjustment of the 24-hour scale through printing or engraving it on a rotatable external bezel offers the flexibility to advance or rewind the time indicated by the GMT/24-hour hand. As a result, it becomes possible to display two different times simultaneously.

With the introduction of an independent hour hand, two new options emerge. The first option involves adjusting only the hour hand when entering a new time zone while keeping the GMT hand & bezel unchanged. 

This configuration allows the GMT hand to display your home time aligned with the unadjusted 24-hour bezel. In contrast, the regular hour hand indicates the local time on the main dial. It is important to note that, in such cases, the minute hand remains unaffected.

The second option enables the simultaneous display of three time zones by adjusting the GMT/24-hour hand & the bezel. However, reading this configuration can prove challenging, mainly if no static 24-hour scale is printed around the dial's edge. 

When rotating the 24-hour bezel on a watch without a static scale, the reference point for the 24-hour hand also changes, requiring additional mental effort to read three time zones simultaneously on such watches.

How Does It Work On The Rolex GMT-Master?

In this particular scenario, the regular hour hand serves as a representation of your local time. The GMT/24-hour hand & the bezel can be disregarded, allowing you to read the time as you usually would as if they were entirely absent.

The GMT/24-hour hand indicates the second timezone & its position on the 12-hour dial (or the 24-hour bezel for 2 timezones). For instance, let's assume it's 1 pm in your local timezone & 3 pm in your second timezone. The regular hour hand will point to the 1 o'clock marker on the dial. 

Meanwhile, the second hand will be between the 7 & 8 o'clock markers, indicating 15:00 (the 7 o'clock marker on a 12-hour dial corresponds to 14 o'clock on a 24-hour dial; the 8 o'clock marker corresponds to 16 o'clock; therefore, 3 pm, or 15 o'clock, falls in between the two).

If your 12-hour dial features a 24-hour scale printed around its edge, determining the corresponding value for the GMT hand becomes significantly easier. Although it requires a swift calculation, this method is perfectly feasible for watches such as the Rolex GMT-Master II that do not have a fixed 24-hour scale.

The next step in mastering the triple-timezone method is somewhat more intricate. However, it is imperative to adjust the rotating bezel to display the third zone against the second (not the first - please bear in mind that the 24-hour bezel solely functions with the 24-hour hand). 

Assuming it is midnight in your third preferred timezone, rotate the 24-hour bezel until the 12 o'clock triangle aligns with the GMT-24-hour hand (which, in this example, currently indicates 15 o'clock or between 7 & 8 o'clock).

As a result, the bezel number at the conventional 12 o'clock position corresponds to 9 am (presumably indicating a dot or space between 8 & 10). This signifies a time difference of 9 hours between your second & third time zones, which, upon adding 9 to 15 to achieve 24, is confirmed to be accurate.

The Rolex GMT-Master & Rolex GMT-Master II

Rolex & GMT-Master II models are highly coveted timepieces in the watch industry. They have adorned the wrists of historical icons & have served as an inspiration for numerous other GMT watch styles. Nevertheless, no other GMT model has achieved the excellence that Rolex's watches embody.

The bezel configuration widely recognized as the "Pepsi" is among the most renowned. It features a horizontal split between red & blue segments, with the blue indicating nighttime hours & the red representing daylight hours (approximately). 

This split-bezel arrangement, available in several colors, is a customary feature across the range. However, the most notable variations found within the Rolex catalog include the Pepsi, the "Coke" (black & red), the "Root Beer" (black & brown), & the "Batman" (black & blue).

All Rolex GMT watches present a consistent overall aesthetic, regardless of their color profile. However, the primary distinction between the GMT-Master & the GMT-Master II lies in their time zone capabilities. While the original GMT-Master can display two time zones, the GMT-Master II can showcase a third, thanks to its independently adjustable hour hands. 

Moreover, the convenient jumping feature of the 12-hour hand allows for seamless time zone adjustments during travel without compromising the watch's precision.

When determining the suitable Rolex GMT watch for you, the decision rests solely in your hands & will primarily hinge upon your lifestyle & wearing preferences. Nevertheless, it is essential to note that both models are renowned icons in the realm of watches, boasting Rolex's legendary craftsmanship & longevity.

Why Buy Rolex GMT Master From Time Source Jewelers?

At Time Source Jewelers, we understand the importance of owning a Rolex GMT Master. As one of the most highly sought-after timepieces in the world, a Rolex GMT Master makes a statement & serves as a reliable tool for tracking multiple time zones.

We take pride in our extensive collection of Rolex watches, including various models & color combinations of the GMT Master. Our team of experts is passionate about helping our customers find their perfect Rolex timepiece, & we offer competitive prices to ensure that owning a GMT Master is within reach.

In addition to selling authentic Rolex watches, we provide maintenance, repairs, & customizations to make your GMT Master unique.

Don't settle for anything less than the best when buying your Rolex GMT Master. Shop with us at Time Source Jewelers & experience the luxury & excellence of owning a Rolex watch for yourself. 

So, if you're looking for a timeless timepiece that combines style, functionality, & precision, consider investing in a Rolex GMT Master from Time Source Jewelers. We guarantee you won't be disappointed! So, what are you waiting for? 

Visit us today & find your perfect Rolex GMT Master. Happy shopping!