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Watch 101

Rolex Sky-Dweller: What Is an Annual Calendar?

Paul Altieri

Few companies know how to keep a secret quite like Rolex. The world’s most recognizable watchmaker is notoriously tight-lipped about pretty much everything that goes on behind its doors; from the number of models that it makes each year, to the sheer scale of its profits, and most certainly the new pieces waiting in the wings to launch. Consequently, everyone was taken completely by surprise when the Rolex Sky-Dweller dropped in 2012, the first all-new watch (with an all-new name) to be released in more than a generation. 

In fact, in the run-up to that year’s Baselworld, it was only actually the Rolex Sky-Dweller name that was known. Understandably, given that the brand’s other ‘Dweller’ (the Sea-Dweller) was a more beefed-up version of the Submariner, many were expecting a sturdier take on the GMT-Master II, their all-conquering aviator’s model. What we got instead was something that out-flagshipped the President – a watch that shared the Day-Date’s sleek, dressy lines but which contained Rolex’s first-ever annual calendar complication. 

Rolex Sky-Dweller Annual Calendar Complication Blue Dial
What is the annual calendar complication on the Rolex Sky-Dweller?

What is an Annual Calendar?

There are several different types of calendar complications in mechanical watchmaking. The simplest and by far the most common are those which just show the date of the month, and which have to be advanced manually should that month have fewer than 31 days. Rolex really started it all with the Datejust back in 1945, but the function has since gone on to develop into several diverse forms adopted by most other manufacturers, with alternatives such as the Big Date (which uses two wheels to display the numerals) or the above-mentioned Day-Date – another innovation pioneered by Rolex, which has both the standard month numeral, plus the day of the week spelled out in full, located in a separate aperture.

Rolex Sky-Dweller - What is an annual calendar complication?
The Sky-Dweller’s movement adjusts for months with 30 and 31 days.

At the other end of the scale (putting aside Moonphase complications for the moment) we have perpetual calendars. These are the set-it-and-forget-it models that not only compensate for the differing number of days in a month and regulate themselves accordingly, they automatically adjust for leap years as well, leaving the wearer nothing to do to keep the various calendar functions accurate.

In between those two is the annual calendar. These don’t recognize leap years but do surpass the standard variety in that they mechanically correct for the months with 30 and 31 days in them. As such, they only need manual intervention once per year – at the end of February. As the median option in terms of convenience, annual calendars are likewise right down the middle when it comes time to price. On average, they are certainly more expensive than the bare-bones calendars, but they are usually far cheaper than perpetual calendars, whose incredibly intricate inner workings generally come with an equally incredible price tag.

Rolex Sky-Dweller Annual Calendar Complication Stainless Steel
On new Sky-Dweller watches, the GMT disc is now finished in a similar color to the dial.

The Annual Calendar in the Rolex Sky-Dweller

Perhaps the most impressive thing about the Rolex Sky-Dweller is that, on top of its annual calendar, a GMT function has also managed to be included in its 42mm case, which requires no additional push-pieces to aid with the setting process. Having extra pushers flanking the crown (like the Daytona) or small buttons flush with the side of the case (like the Cellini Moonphase) is the go-to way for manufacturers to allow access to the additional functions of a watch movement; however, the Rolex Sky-Dweller uses the brand’s Ring Command bezel, which links directly to the Cal. 9001 movement within – a technology that first debuted on the Yacht-Master II in 2007, to facilitate the setting process. 

Stainless Steel Rolex Sky-Dweller Annual Calendar Complication
The Ring Command bezel on the Rolex Sky-Dweller is linked directly to its internal movement.

The bezel on the Rolex Sky-Dweller takes the Ring Command concept one step further and becomes a full-on analog function selector. Rotating the surround between its three positions unlocks each one of the watch’s various operations, enabling the wearer to set them with just the crown – and means that it is able to keep its dress watch profile without any supplementary push-pieces on the case. As the ultimate luxury travel timepiece, the Sky-Dweller was always destined to be part of the dress watch collection rather than a sports model. Indeed, it could easily be mistaken for the President at first glance, complete with the brand’s iconic fluted surround.

The Cal. 9001 is the most complex movement that Rolex currently manufacturers, and cramming so much information onto a dial has called for some inventive use of space. Consequently, both of the major complications have taken on new forms not seen anywhere else. As always with Rolex watches, efficiency has been uppermost in the designers’ minds.

Rolex Sky-Dweller White Gold Annual Calendar Complication
The Cal. 9001 packs a lot of functionality into a relatively clean display.

The dual time zone, which on the GMT-Master II is taken care of with the use of a secondary hour hand pointing to numerals on the bezel, is instead displayed on a rotating, off-centered 24-hour disc on the Rolex Sky-Dweller. A small red triangle below the 12 o’clock marker points to the correct time. As innovative as the system is, it is also the styling element that has polarized opinions the most about the watch, and later versions have toned down the feature by making it the same, or at least a similar, shade as the rest of the dial.

But it is the proprietary annual calendar complication (named SAROS) that has made a complex challenge so impressively easy to read. Instead of an additional window with the month spelled out as you will find on other watches of this type, the company has used the hour indexes themselves as references. Above each one of the twelve indices is a small opening which is filled in in a different color for its corresponding month. So, the gap above the one o’clock marker represents January, two o’clock is February, etc. It is one of those I-can’t-believe-no-one’s-thought-of-it-before arrangements for which Rolex is so celebrated, and it means that the Sky-Dweller remains extremely legible for a watch with so much to do.

For a manufacturer really only now dipping its toes into the world of advanced complications, it is fairly remarkable and may be pointing to where they are headed in the future. Rolex has built its reputation by creating some of the most iconic yet simple watches in the industry, something that has gained them both a fiercely loyal fan base as well as a fair number of detractors – those who decry their supposed lack of engineering flamboyance. The Rolex Sky-Dweller is a spectacular response to this latter group, one of the most intelligently designed and executed annual calendar watches in the industry. For those who enjoy a true jet setting lifestyle, there are few better companions on the market. 

Rolex Sky-Dweller annual calendar saros luxury travel watch
The Rolex Sky-Dweller is the ultimate luxury travel watch.

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Paul Altieri