Mechanical Watches, Daylight Saving Time, And Why DST Complications Are So Rare
When it comes to watches and watchmaking, springing ahead and falling behind is harder than it looks.
Daylight Saving Time is as we all know, the practice of setting clocks one hour ahead in the spring, and setting them back an hour in the fall. The rationale for the practice is that as days get longer, setting clocks ahead will extend the number of useful daylight hours – sometimes you hear people say that the idea was implemented to give farmers a longer working day during peak growing season, although the practice, which was widely adopted during World War I, was also thought to help save energy. An interesting factoid in the history of DST is that one of the earliest proposals came to us courtesy one George Vernon Hudson, an entomologist in New Zealand who proposed the idea to the Wellington Philosophical Society in 1895. My source for this writes, “His shift-work job made him aware of the value of the daylight hours,” and certainly, an extra hour of useful daylight in the afternoon leaves more time for entomologizing in the field.
It’s less clear that there’s a solid reason for continuing the practice today; for one thing, it’s physically stressful to change the clocks as it messes with the body’s circadian rhythms, which govern among other things, cycles of alertness and rest. I always like to trot out a couple of papers to support this view, including one from the University of Groningen, entitled, “The human circadian clock’s seasonal adjustment is disrupted by daylight saving time,” and one from Business Insider which points out that there is a spike in heart attacks of over 20% the Monday after the Sunday when we “spring ahead.” In short it seems to me – your mileage may vary – that not only is there no real benefit to the practice, but that it also does more harm than good (although in the USA the Department of Transportation asserts that since there is more daylight during afternoon and early evening commutes, DST reduces traffic accidents. Where the clock change has been done away with, the tendency seems to be to just make DST permanent year round, which avoids upsetting biological clocks but keeps the benefits, if any, of DST intact).
Daylight Saving Time poses a problem for watchmakers, albeit it is a highly particular problem. Specifically, DST is an issue for world time watches, which typically show the time in 24 time zones around the world and in particular, in reference cities on a disk around which a 24 hour ring rotates. The existence of DST means that most world time watches will show the incorrect time for any city that observes DST for half the year, which is a little unsatisfying intellectually although it is possible to comfort yourself with the idea that since DST is defined by legal statute rather than astronomical reality, the discrepancy should not interfere with the pleasure you take in your world time watch (this is slightly cold comfort since time zones themselves are defined by legal statute rather than astronomical reality, but you take your joy where you can).
There are a few workarounds. One of the more common is to simply have an indication on the dial of a world time watch which shows which cities observe DST – usually the city name is in a different color, to make it easier to distinguish from cities where DST is not in effect. Vacheron Constantin uses this approach in its Traditionelle World Timer. IWC’s Timezoner has a rotating bezel for changing the date and time, and for cities that observe DST, there is a small dot adjacent to the city name with a small letter S (for Summer); when changing the reference city, if DST is in effect you just make sure that the dot, rather than the city name, is at 12:00.
Probably the most realistic workaround for most use cases, if you really don’t want to have to worry about your watch showing the wrong time for a city in a different time zone, is to just use a standard GMT watch with an independently settable hour hand. This takes care of local time although you still have to reset the watch twice a year when the clocks change, if you want the 24 hour home-time hand to be in the right position when you travel (and of course, for the local time to be correct).
Actual attempts to mechanically cope with DST are few and far between. One very unusual example is Glashütte Original’s Senator Cosmopolite; the watch has a home time display in a subdial at 12:00 and a central display of local time. The watch is not a world timer in the narrow sense but it is a GMT/Dual Time Zone watch with a couple of cool party tricks. The first is that the local time hour hand can be jumped forwards or backwards in fifteen minute intervals which means that unlike just about every other GMT watch out there, you can set local time to all 37 time zones, even the ones with non-full hour offsets from GMT.
The second is that there are a couple of windows labeled DST and STD (daylight saving and standard time) which show three digit airport IATA codes for airport in all 37 time zones. When re-setting local time, you just make sure that your reference airport is in the correct window; the codes switch automatically when you change the time so as long as you make sure that EWR (for instance; Newark) is in the DST window when the USA is observing DST, you are good to go.
The only world timer that I know of that has an actual mechanical solution for DST is from Bovet and the watch is the Récital Prowess 1, which Greg Gentile covered for us last April. The watch shows the time in 24 time zones, but does so via a system of rollers which can be rotated by pressing the crown. When you do so, the correct city for DST or standard time rotates into position next to the fixed 24 hour disk (and on top of everything else, the watch is a tourbillon with perpetual calendar as well).
Practically speaking the most complete wristwatch solution is a multifunction quartz watch but there is something fascinating about how watchmakers have attempted to cope with the ramifications of the time zone system as well as DST. If you want to show the time in all 37 time zones simultaneously and you want your watch to be able to show where and when DST is or is not in effect, you have your work cut out for you and most watches represent one compromise or another (only 24 time zones instead of all 37; DST adjustment but only for 24 time zones; all 37 time zones but no mechanical DST complication, and so on; the Senator Cosmopolite comes pretty close although strictly speaking it’s a GMT watch, not a world timer, and the 15 minute jumps mean more fiddling with the crown than with a GMT watch that has full hour jumps).
I suppose the Holy Grail of world time complications would be a 37 time zone world timer, with the ability to show in each time zone whether or not DST is being observed in the reference city but I certainly can’t figure out what that would even look like, let alone how it would work. And of course, all it would take is the stroke of a legislative pen, changing the time zones for a given city or doing away with (or making permanent) DST, to make such a watch obsolete. Still, though, I hope someone tries; think of the Wow factor.