The reason we have leap year has to do with keeping consistent time – sort of like a watch. By adding a day once every four years to our Gregorian calendar, we keep our measured time in alignment with the Earth’s revolutions around the sun. It takes the Earth approximately 365.242189 days – or 365 days, 5 hours, 48 minutes, and 45 seconds – to circle once around the Sun. But the Gregorian calendar consists of only 365 days in a year, so if we didn't add a leap day on February 29 nearly every four years, we would lose almost six hours off our calendar every year. After only 25 years, our calendar would be off by around 6 days.
To measure days and dates accurately on our wrists, many brands offer calendar watches that can track the days, date, months and more. What the calendar watch offers depends on whether it is an annual calendar or a perpetual calendar. Either way, calendar watches can be a very useful companion in today’s busy world.
Essentially the annual calendar watch tracks the information of each month on the wrist, including offering day, date and month – taking into account months that are 30 and 31 days in length. However, this type of watch requires a resetting of the date every year at the end of February (which can, of course, be 28 or 29 days long, like this year).
Baume & Mercier’s Clifton Complete Calendar is a beautiful example of form and function when it comes to an annual calendar. The self-winding mechanical watch – offered with either a white or anthracite dial – tracks day, month, date and moon phases. It is powered by the Swiss-made Dubois Depraz 9000 movement that boasts a 42-hour power reserve. At 43mm, the polished/satin-finished steel casing features a sapphire crystal both on the front as well as the back for viewing the movement.
Most perpetual calendars will even track all of the same information and more besides, including the leap year. With a perpetual calendar, the watch mechanism changes the date no matter how many days are in a month, and can track precisely when it needs to offer one more day in the February line up in a leap year. Generally, perpetual calendar watches will not need an adjustment until the year 2100, when – due to the calendar adjustments to keep time constant – we will skip a designated leap year so that solar and real time are once again brought into line.
Perpetual calendar watches are very complicated to build and so are generally created in limited production. The new Jaeger-LeCoultre Master Ultra Thin Perpetual watch is a great example of perpetual calendar watchmaking prowess. Powered by the
Jaeger-LeCoultre automatic Caliber 868, the watch is a stunning ultra-thin timepiece that, when cased, measures just 9.2mm in height. This is a huge feat considering that the movement consists of 336 pars. The watch offers indications of the year, date, day, month, moon phases, as well as hours, minutes and seconds. It is water resistant to 5 bar and is finished with a black alligator strap.
Another beautiful combination perpetual calendar/ultra thin watch is the Audemars Piguet Royal Oak Perpetual Calendar ultra-flat watch. A work of art, balance and craftsmanship, the timepiece is offered in four versions: two each in gold and steel. The 41mm watch offers astronomical moon indication, on an aventurine dial, that is so precise it will not need an adjustment for 125 years and 317 days.
It also offers day, date, month, and leap years, as well as all the other calendar goodies – including the weeks of the year on an outer chapter ring for those who need to refer to week numbers in business. The watch houses the ultra-flat, 374-part Caliber 5134 movement that is just 4.31mm thick thanks to a suspended barrel. The bidirectional self-winding movement offers 40 hours of power reserve.
Any one of these will suit your needs for this leap year and many more to come.
