The most common wristwatches are based on a 12 hour system. In those watches the hand indicating the hours makes a complete rotation in 12 hours hence two complete rotations per day. There are other watches, however, that are based on a more natural 24 hour cycle in which the hand indicating the hour makes a complete rotation in 24 hours. Sometimes the two systems are used combined in the same wristwatch like in the GMT or in the dual time watches. The key question is why the 12 hour system is the most widely used and not the 24 hour one? what are the advantages of a 24 hour system based watch? And ultimately why do some people use 24 hour time watches?
For the purpose of this article we will generalize and define “pure players” or “pure” the watches that are based on one single system (either 12 or 24 hour) and will focus on those rather than the watches that use a combination of the two.
The 24 Hour Clocks
Back to our key question - why do people use 24 hour time watches? Some people just like them either because different or because they find the 24 hour based system easier to use. Others, instead, need those watches for a specific and often technical reason.
People who cannot see the sky or who travel across time zones might find a 24 hour dial very useful. Those dials can help them understand whether it is night or day at a glance. For example explorers who have to spend time in environments without access to the sky (e.g. caves), in the “sky” (e.g. astronauts) or in places in which the passage of time cannot be easily grasped through the movement of the sun (e.g. arctic) might be the principal users of this kind of watches. Another immediate benefit of the 24 hour dials, especially for scientists and explorers, is the fact that those timepieces can be used very easily as a compass. Via pointing the hour hand toward the sun one can find the North position where the 24 hours mark is (midnight mark) – maybe the simplest way to combine a compass with a watch!
In general, the 24 hour time system is used whenever people want to specify the time precisely and unambiguously to prevent errors caused by confusing or omitting the AM/PM suffixes. This is the case, for example, of the military forces who use the 24 hour based system for all their operations – and this is also the reason why sometime people refer to military watch to talk about 24 hour system based watches (mostly US and English speaking countries). The 24 hour system is also referred to as the continental time and railway or railroad time. This is in fact the first system that has been used to standardize timing across geographies and the railway was the main driver of this harmonization.
Ultimately the layout of the 24 hour clocks is more natural, with the dial representing a full day. This kind of dial makes easier to grasp the passage of time as the day progresses with each half of the dial representing either day or night time.
Interesting to note is that the 24 hours dials have a long history while the 12 hours dials have been introduced only lately. There seems to be lots of argument for the introduction of the 12 hour based system but not a crystal clear reason – in this excellent article about the history of 24 hour watches you can find a list of reasons, arguments and objections about the implementation of the 12 hour system.
Nowadays 24 hour clocks are fairly uncommon, mainly driven by the low consumer demand. People are by now very well acquainted with the 12 hour system that would not be that easy for them to switch from one system to the other – they are so accustom with the 12 hour system that they can read a watch dial even without number markings on it. Another reason for the low penetration of 24 hour clocks is the difficulty in finding 24 hour movements available off-the-shelf. Most 24 hour watches use in-house movements, repurposed GMT movements, or a custom motion work. Only few movement manufacturers make “pure” 24 hour movements like the 2893-2 by ETA or 515.24H by Ronda (both Swiss movements).
Watches that are based on the 24 hour time system might indicate the hours with 1 to 24 / 0 to 23 numbers on the dial or might indicate hours as 1 to 12 twice with some sort of AM/PM indication (double-XII system). For reference AM stands for Ante Meridiem (Latin for before the middle of the day) and PM stands for Post Meridiem (after the middle of the day) and are used to differentiate day hours from night hours in a 12 hour based system.
The Different Kind of Players
The very “pure players” watches are single-handed. Those watches have only one hand on the dial and it takes 24 hours to the hand to make one full revolution – this hand indicates the hours. There are no hands to indicate seconds or minutes though sometimes they might have a date indication. This kind of watches might appear unconventional but measuring the passage of time with a single hand was in fact the norm when the watch was just invented. For long time, starting with the sun dials, the watches have been measuring only one thing – the hours. Only at a later stage watches started becoming more complicated and started indicating other elements like minutes and seconds.
Examples of 24 hour clocks "pure players" are Botta Design, Slow-watches or the more prestigious Jacquet Droz “Grande Heure” or the Chris Wiegman’s single-handed Life Clock which is based on the double-XII system (all others are based on the 24 hour system).
There are also two or three handed watches that have a 24-hour dial. The hour hand still takes 24 hours to complete a rotation while the minutes and seconds hands indicate the traditional time revolving once an hour or minute respectively. Examples among those last include the renowned Raketa (Russia), Volmax Aviator (Russia), Vostok (Russia), Fortis (Switzerland), Glycine (Switzerland), Ollech&Wajs (Switzerland), Airnautic (by Ocean 7), Gruen (US), Dolphin Watches, Poljot Aviator (Germany), Messerschmitt 262… Interestingly many Russian brands play in this category like the famous Raketa which manufactures watches since 1962 with movements entirely made in house. Raketa watches were produced for the Red Army, the Soviet Navy, for North Pole expeditions, as well as for civilians.
The bulk of the pure players is based on a 0-23 or 1-24 numbering system and there is a great deal of variation on the orientation of the dial concerning the position of noon vs midnight. The major part of those brands generally shows midnight at the top despite this being less intuitive (at noon the sun reaches the zenith hence should be indicated on the top). Few brands place the 24 mark on the left or right which makes night vs day separation vertical instead of horizontal. Also, most of them do not feature 24 numbered labels, since this might results in a very crowded dial and for this reason they generally alternate even numbers with odd markers.
On top of the pure players there are also 12-hour watches with a third hand to operate a 24 hours cycle. This can be used for example for a second time zone like in the GMTs. GMT stands for Greenwich Mean Time and is the "0" point on the 24 hour scale of international time-zones. Greenwich is in England, and the time in geographies in different time-zones is calculated as plus (+) or minus (-) compared to the GMT. GMT watches show two time-zones at once, generally those are the GMT and the local time but people might indicate two totally independent zones. Many GMT watches have also a rotating bezel that can be used to track a third time zone. This category of watches is much more common and almost any brand is playing in this segment.
Todd & Marlon Perspective
We believe that watches based on the 24 hour system will not increase their popularity dramatically over time. Thanks to the marketing effort of some new players (e.g. slow-watches) the category might expand but the use of those watches will still remain limited to the true passionate and to the people who really need them. 24 hour clocks are and will remain exclusivity of few – few who will stand out of the crowd!
We also believe that 24 hour time clocks might help people improve their time management skills and ultimately bring back some balance in their life (see our other article #1 secret to live life to the fullest). Monitoring time on a full day scale is very mind opening and can help people realizing how much time they spend on things that might not be the top priority or most urgent and important things to do and might lead to a change in people life (we hope). Notably, the successful entrepreneurs are among the best in managing time and they could further strengthen their skills with a 24 hour watch.
The first collection of Todd & Marlon watches (#YOURTIME) uses 2x12 hour marks with midday indicated at the top via an applied silver sun icon and midnight at the bottom as indicated by an applied moon silver icon. The left hand side hence represents the morning hours (1-12 Am) and the right hand side the afternoon hours (1-12 PM) - both clearly indicated by the main numbering system. In #YOURTIME watches both minutes and seconds are indicated with hands pointing to a secondary numbering system (red numbers) - see also our post about how to read a 24 hour watch
As you might have noticed we have chosen a very peculiar and uncommon design. Most of the commercially available 24 hour wristwatches, in fact, are based on a 0-23 or 1-24 numbering system and do not show all numbers (they mix numbers and marks). On the other hand Todd & Marlon watches are based on the Double-XII system and all hours are clearly indicated (as well as minutes and seconds in the secondary numbering system).
Thanks to this design we have combined the best of two worlds. #YOURTIME watches offer all the benefits of a 24 hour watch and at the same time they still have a close reference to the way people talk about timing while clearly indicating the time. Most people still refer to time on a 12 hour scale making reference to AM vs PM or morning vs evening. Only in few places or few people refer, for example, to 19:00 when talking – the major part of people would rather say 7pm or 7 in the evening. In other words #YOURTIME watches talk the language of the bulk of people while offering them the benefit of a 24 hour watch. On top, the clearly indicated hours and minutes/seconds can facilitate the move from a 12 hour based system to the 24 hour system.
This is the reason why we would recommend a Todd & Marlon but be warned though! Once you get hooked on the 24 hour dial, you will never want to wear a 12 hour watch again. Now it is #YOURTIME to evaluate whether to make a change and move to a more natural 24 hour time based watch or to keep the status quo!
In the mean time if you want to know more about 24 hour watches you can refer to the following resources:
24hourtime.info is a very comprehensive site about 24 hour analog clocks. With information about: where to buy 24 hour analog clocks and watches, and where to see some of the more famous examples. There is also a great history page and a Software page, with links to some software clocks that offer 24 hour analog capability.
Russian24Hour site dedicated to the Russian 24 hour clocks (not for sale – see next resource).
Russian Watches site about Russian watches – mostly 24 hour system based watches made in Russia. This is also an e-commerce site for the Russia watches.
Wikipedia informations about 24-hour analog dial: history, design and 24 hour clocks in general.
Watchuseek 24 Hour Watches Forum has been designed specifically to talk about 24 hour clocks