What is a Calendar Watch?

When you look at a modern watch, there is a good chance that it has one of the calendar functions. There are a variety of calendar functions, but they all serve the same purpose: to tell you the date, the day of the week, the month, or the year. This blog will provide you with a brief overview of five of the calendar functions you can find on a watch, in order of how complicated they are, and therefore, how expensive they are likely to be.

Date Watches

Date watches are the simplest, and most common type of calendar watch. The date function tells you which date of the month it is. The first date watch was patented by a watchmaker called Hammerly in 1915. The date was displayed in the outer-ring of the watch, where the minute and hour indices were. The date was pointed at by an additional hand. This is called a “pointer-date”. However, the date did not adjust automatically. It needed to be adjusted every day by the wearer.

The next evolution of the date watch was the introduction of a little window to show the date. This is unsurprisingly called the date-window. The first watch to use the date-window was a watch by a now-defunct brand called Mimo, in the 1930’s. It wasn’t until Rolex released the Datejust watch in 1945 that a watch with a date-window automatically updated the date every day. The Datejust is Rolex’s biggest selling watch to this day. Now, you can find the date displayed in a variety of ways on a watch dial; however, the most common methods are the pointer-date, the date-window, and a sub-dial.

Day-Date Watches

The day-date function is also very popular and widespread on watches. It combines a date display, with an additional window or sub-dial that displays the day of the week. The first watch with a day-function was released by Hammerly, at the same time as they released a watch with a date function. This was the first day-date watch. The most famous day-date watch is the Rolex day-date, which was released in 1956, and has been worn by a string of US Presidents. If you want to read more about day-date watches and how they work, we’ve written a blog, which you can find here.

Triple Calendar

A triple-calendar combines a day-date function with a month indicator, which means the watch will display the date, the day of the week, and the month. A triple calendar needs to be adjusted five times a year, as it displays every month as having 31 days. That means that every month with fewer than 30 days needs to be manually adjusted for: February, April, June, September and November. It is believed that the first triple calendar wristwatches were released by Rolex and Vacheron Constantin in the 1920’s. Vacheron Constantin is still know for making beautiful triple calendar watches, based upon a model they released in the 1940’s during a period of great popularity for triple calendar watches.

Some triple calendar watches also include a moonphase indicator, which displays where the moon is within its monthly cycle. When a moonphase is included, then the triple calendar watch is often called a complete calendar. Hamish, our CEO, has a beautiful Jaeger-LeCoultre Complete Calendar watch.

Annual Calendar Watches

Like a triple calendar, an annual calendar watch displays the date, the day of the week and the month. However, unlike the triple calendar watch, and annual calendar will automatically adjust between displaying 30 or 31 days in the month, without the need for adjustment. This means that an annual calendar watch will adjust from the 30th of April to the 1st of May automatically, and then from the 31st May to 1st June, again, without the need for human intervention. An annual calendar watch will need to be adjusted on the 28th of February to either the 1st of March, or the 29th of February during a leap-year.

The annual calendar watch is relatively new compared to the other types of calendar watch. It was invented in 1996 by Patek Philippe. The watch was the Ref: 5035, and was actually designed by a Swiss University student as a year-end project. The student went on to work for Patek, who released the watch commercially. You can read more about annual calendars and that particular watch here.

Perpetual Calendar Watches

The most complicated calendar watch that we’ll briefly explore in this blog is the perpetual calendar. Like the annual calendar, they display the date, the day of the week and the month. In addition, they also display the year, which means a perpetual calendar can also adjust for leap-years by automatically displaying the 29th February once every four years. This is an incredibly challenging mechanical feat, which means perpetual calendars are usually very expensive watches.

Patek Philippe also created the first perpetual calendars in wristwatch form. A one-off special order was created for a client in the 1920’s, and then the first serially produced perpetual calendar watch was released in 1941. This was the Patek Philippe Ref: 1526, and is considered by many collectors to be a holy grail watch due to is limited production run of 210 pieces and historical importance.

Conclusion

We at The Watch Collectors Club are here to help you learn more about different types of watches. Calendar watches are very useful, and often beautiful. If you want to see some in real-life, make sure to sign up to our next in-person event. You can find the details here of all of our upcoming events.

If you’ve enjoyed this blog, please send it on to anyone you know who likes watches. This is a club for everyone who likes watches.