I travel frequently and have been considering buying a GMT or a world timer watch. However, I had a sneaking suspicion of world timers: how do those pretty rings of city names deal with daylight savings times and other switches? Is this just a detail or is it frequently incorrect? With my OCD focus on detail I would not be able to ignore the fact that cities are off by an hour, so I wanted to know how big a problem it would be.

After a little bit of programming, I can tell you: it's a mess. Not only are many of the cities wrong for much of the year, but timezone rules change often enough that even if you could come up with a way to reflect the worldwide rules at any moment, it would be out of date long before you handed it down to your kids, and possibly before your first service.

I looked at two watches, selected without a lot of care: the NOMOS Zürich World Time and the Omega Seamaster Aqua Terra Worldtimer.

For each of the watches, I transcribed the 24 locations they used for the timezones around the globe and mapped them to the timezone rules for that locale. Then I calculated the local time in those cities at midnight London time and checked to see if the local time aligned with the offset from London on the watch face. I checked a number of dates in 2018 in all four seasons. In the spring or fall, it's not so bad, but there are still errors:

March 10, 2018 at midnight London time, either of these watches would say it's noon in Auckland, but it's actually 1pm there, as New Zealand observes daylight saving time until April 1. But a month later on April 10, Britain has begun DST and now it's off by an hour in the other direction: at midnight London time, the watch will say it's noon in Auckland, but now it's 11am there. On March 10, 2018, the NOMOS would be off by an hour in Sydney, Auckland, and Santiago, and the Omega would be off by an hour in just Sydney and Auckland.

However, when one gets into summer or winter months, things get a lot more ugly. On today, June 10, 2018, each of these watches is off on 15 of their 24 time zones: more than half! If you own one of these watches hoping it will tell you the time in other cities, and set it based on a continental US or Western Europe city, it will be off by an hour more often than it will be right. Specifically, they'll each show a time an hour later than the actual time in Moscow, Dubai, Karachi, Dhaka, Bangkok, Hong Kong/Shanghai, Tokyo, Sydney, Noumea, Auckland, Pago Pago/Samoa, Honolulu, Santiago/Puerto Rico, Sao Paulo, and DeNoronha/South Georgia.

This doesn't seem solvable: the idea of 24 painted city names actually reflecting local times around the globe is romantic but unrealistic; in practice, it's useful for a rough approximation (within an hour or at most two) and nothing more.

 

Both

 

Personally I prefer GMT watches cleaner and depending on how it’s set up you can track 2-3 time zones on them. Although those wierd 1/2 and 1/4 hour ones in Tibet and India are a lost cause.

 

I had the JLC Master Compressor Geographic. With all of their Geographic models, you can 'map' out the time difference between your home and another city on the city dial.

Yes, there are some 'issues' if you flip between cities that respect daylight savings time and others that don't.

Not a perfect system, but DST wasn't designed with perfection in mind.

 

Now factor in places like Arizona that don't do DST.

 

When I first started this global thing I wanted watches that had the 24 hour dial so I wouldn’t miss my flights or trains ... then gmt watches or those with a second time zone so I would not wake my wife up at 2 am. Now I have my I Phone and I can approximate time difference in my head pretty much anywhere. When I travel now, my trusty Rolex GMT Master II is most often on my wrist but sometimes I dispense with it and just wear one of my modern watches. Buy a world timer because it looks cool. Not as an actual tool for calculating time zones. (You will miss a lot of meetings that way)

PS .... the best thing a GMT, Second Time Zone or world timer really saves you from is impulsively drunk dialing friends and family.

 

QLD in Aus doesn't because it upsets the cows and too much sun fades the curtains.

In 1992
The late premier Joh Bjelke-Petersen insisted the “extra” hour’s daylight faded curtains while in an appeal to dairy farmers claimed their cows needed to be milked an hour earlier for the milk to be collected on time.


The NT ( norther territory) doesn't do in because
NT time is
Not Today
Not Tomorrow
Next Tuesday

 

Mine was last accurate in 1953, before Calcutta and Bombay merged time zones. They're not even known by those names anymore...

 

My grail Tissot

If it is capable of that, you're not drunk enough...

 

It does become a pain certainly, which is exactly why I ended up buying a Citizen Navihawk; the radio signal would automatically update all the info.

Now, if we somehow got rid of the damn DST/SMT/Whatever, those beautiful mechanical timepieces can certainly make a worthwhile comeback, and my lust for a Zenith Double-matic would know no bounds...

 

I find my Seiko indispensable. How else could I tell the time in Noumea?

 

I suspect mostly decorative - for most people anyway. I used to travel a bit when I had a Patek World Time but I would say that I hardly used the watch to monitor time differene etc...

 

Would say both for sure

My Tissot Navigator from 54 with Calcutta and Bombay as one time zone @Vitezi

Btw: I really like the NOMOS, though a bit too large for me

Edit: I have also thought about Daylight Savibg and The facit that this messes things up... Do you think it is solveble with a manual watch? Like a binary choise "summer or winter time in your gone country"?

 

Decorative in my case - by the time I could afford this, I can’t see the bloody time on it any more....

 

It would be pretty complicated; I think it would involve rotating the city names that keep DST by one hour during the summer of the relevant hemisphere. It's hard for me to imagine how it might work. It would still be inaccurate during the seasons when DST starts and ends, as countries vary on when; also the laws change (when looking into this I found that Moscow has stopped observing DST in the last 4 years).

 

Important to know the time in LA when you are snorkelling in er, somewhere else.

 

It seems to me that having two rings - one for DST and one for summer time - would drag the watch halfway to accuracy (maybe 40%) Swap them out every spring and just pretend that Europe and North American don't go on summer time 2 weeks apart! Fire up the CNC machine!

Seriously, though - I see why people with OCD, I mean, people who focus on detail would have a terrible time with these. Some models are wrong 100% of the year!

 

Hi I recently found the patent below for a 'Universal Timepiece'. It varies from the standard world timer by not having an hour hand. I've posted a new thread on it if anyone is interested.

https://omegaforums.net/threads/universal-timepiece.86955/

 

Also, how about world timers where the cities are indicated on the caseback. And it doesnt rotate.

Like the Breitling GMT Navitimer World Time.