In the 1950s, as jet airliners began crossing oceans in hours rather than days, pilots faced a new problem: their bodies were in one time zone, their flight plans in another. The answer was a fourth hand, a 24-hour scale and a rotating bezel. The GMT watch was born, and it has been the traveller's companion ever since.
The short answer: a GMT watch displays a second time zone using an extra hand that circles the dial once every 24 hours, read against a 24-hour bezel or chapter ring. Rotate the bezel and you can track a third time zone. "True" or "flyer" GMTs let you jump the local hour hand when you land; "caller" or "office" GMTs let you set the 24-hour hand independently. Steinhart offers GMT models with Swiss automatic movements.
What Does GMT Stand For?
GMT means Greenwich Mean Time, the solar time at the Royal Observatory in Greenwich, London. For most of the 20th century it served as the world's reference time. Today, Coordinated Universal Time (UTC) has replaced it scientifically, but the name GMT has stuck to the watch complication.
For South African travellers, the maths is easy: South African Standard Time (SAST) is UTC+2 all year round, with no daylight saving.
How a GMT Watch Works
A GMT watch has four hands:
- Hour hand: completes one rotation every 12 hours, showing local time.
- Minute hand: shared by both time zones.
- Seconds hand: shared by both time zones.
- GMT hand: usually a distinctively coloured arrow that rotates once every 24 hours.
Because the GMT hand moves on a 24-hour cycle, it always shows whether it's day or night in the second time zone. Read it against the 24-hour scale on the bezel or the dial.
True GMT vs Caller GMT
This is the distinction enthusiasts debate most, and it matters for how you'll use the watch.
|
Feature |
True / "flyer" GMT |
Caller / "office" GMT |
|---|---|---|
|
What jumps independently |
The local 12-hour hand |
The 24-hour GMT hand |
|
Best for |
Frequent travellers changing time zones |
People tracking a fixed second zone from home |
|
Changing zones on arrival |
Jump the hour hand; minutes and seconds keep running |
Reset the main time; GMT hand stays on home time |
|
Date |
Usually changes with local time |
Varies by calibre |
|
Typical cost |
Higher |
More accessible |
Many widely used Swiss GMT calibres, including the ETA 2893-2, are caller-style. Newer calibres increasingly offer flyer functionality. Neither is better; they're optimised for different lifestyles. Check the specific movement on any GMT you're considering.
How to Set and Use a GMT Watch
Tracking Two Time Zones
- Set the main hour and minute hands to local time.
- Set the GMT hand to your second time zone, in 24-hour format.
- Set the bezel to its zero (24) position at 12 o'clock.
- Read local time from the hour hand, and the second zone from the GMT hand against the bezel.
Tracking a Third Time Zone
Rotate the bezel by the hour difference between your second and third zones. The GMT hand, read against the shifted bezel, now shows the third time.
Example: you're in Cape Town (UTC+2) with the GMT hand on London time. Your colleague is in Dubai, four hours ahead of London in the northern winter. Rotate the bezel four hours and the GMT hand shows Dubai time against the bezel, while the main hands still show Cape Town.
Who Is a GMT Watch For?
- Frequent flyers and business travellers between Johannesburg, London, Dubai and beyond.
- Families spread across continents who want to know when it's a sensible hour to call.
- Remote workers collaborating with offices in other time zones.
- Anyone who wants one watch that does everything: a sports watch with genuine daily usefulness.
A GMT is arguably the most practical complication after the date. It's useful every day, not just on the rare occasion you time an event.
What to Look for in a GMT Watch
- A legible, contrasting GMT hand that stands out from the hour hand at a glance.
- A clear 24-hour bezel, ideally two-tone to distinguish day and night hours.
- A bidirectional rotating bezel for quick third-zone adjustments.
- A Swiss automatic GMT movement that's well proven and serviceable.
- Sapphire crystal and real water resistance, so it's as happy in the sea as in the airport lounge.
The Steinhart GMT Advantage
Steinhart's GMT models combine the classic travel-watch layout with Swiss automatic movements, sapphire crystals and robust steel cases, typically with dive-watch levels of water resistance. Bezel colourways range from understated to the iconic two-tone day-and-night look.
Pair a Steinhart GMT with a WOLF1834 travel case and you have the ultimate kit for the journey: accurate, protected and ready the moment you land.
Frequently Asked Questions
What is a GMT watch used for? A GMT watch shows a second time zone using a 24-hour hand and scale. With a rotating 24-hour bezel, it can also track a third time zone, making it ideal for travellers and people with international connections.
What is the difference between a true GMT and a caller GMT? A true (flyer) GMT lets you adjust the local hour hand independently when changing time zones. A caller (office) GMT lets you adjust the 24-hour GMT hand independently, which suits people tracking a fixed second time zone.
Can a GMT watch show three time zones? Yes. Read local time from the hour hand, a second zone from the GMT hand against the dial, and a third zone from the GMT hand against a rotated 24-hour bezel.
Is a GMT watch good as an everyday watch? Yes. Most GMT watches are robust sports watches with good water resistance, and the second time zone and day-night indication are useful every day.
Conclusion
The GMT watch is the perfect marriage of heritage and daily practicality: born in the cockpit, perfected for the modern, connected life. Whether you're boarding a long-haul flight or calling family overseas, it keeps every place that matters on your wrist.
Explore Steinhart GMT watches on pre-order at pura.co.za, and pair yours with a WOLF1834 travel case for the journey ahead.