Mastering the Rolex Sky Dweller (With Video)

Rolex Sky-Dweller white goldIn the past half-century, since it launched its GMT-Master, Rolex has brought out just two new complications: the Rolex Yacht-Master II, in 2007, with a countdown yacht timer, and the Rolex Sky-Dweller, equipped with both a second time zone and an annual calendar, in 2012. In this feature from our Baselworld 2012 issue, we explain how the Sky-Dweller, and its innovative movement, work.

The Rolex Sky-Dweller contains a new caliber, 9001, which Rolex makes in house. The second time zone is indicated by an off-center, rotating 24-hour disk. Local time, indicated by the center- mounted hands, can be adjusted quickly when you change time zones by setting the hour hand forward or backward in one-hour increments. The minutes, seconds, and second-time-zone indicators are not affected during this operation.

The calendar mechanism, which changes instantaneously (an annual calendar automatically differentiates between months of 30 days and 31 days, and need be adjusted just once per year, at the end of February) is relatively simple, Rolex says: the company has added just two gear ratios and four gear wheels to its existing instantaneous date calendar. As Rolex explains it, “The mechanism is designed around a fixed planetary gear wheel at the center of the movement. A satellite wheel engages with the planetary wheel and rotates, orbiting the planetary wheel in one month, driven by the date disk. The satellite wheel is fitted with four fingers for the four 30-day months (April, June, September and November). Click on watch photos for larger images.

Rolex Sky-Dweller White Gold - front

Click here to watch the Rolex Sky-Dweller video…

“The gear ratio between the satellite wheel and the planetary wheel is calculated in such a way that at the end of each 30-day month – and only in these months – one of the satellite’s fingers receives an additional impulse from the date-change mechanism. This makes the calendar disk jump two days (from the 30th to the first) within a few milliseconds to display the correct date.” Rolex has dubbed the mechanism “Saros,” a Greek word that refers to the approximately 18-year cycle that can be used to predict when eclipses will occur. Rolex chose the name because it brings to mind the revolutions of the Earth and moon, which are like the motion of the satellite wheel (the Earth) with its four fingers (the moon).

The Rolex Sky-Dweller calendar has an unusual month display. The hour numerals correspond to the 12 months of the year. Next to each numeral is a window. The window for the current month (e.g., “IIII” for April,) is black; the other 11 windows are white. (On the brown-dial model, the correct month is indicated by a white window for better contrast.)

Rolex Sky-Dweller white gold - dial detail

The month is shown by a window next to the corresponding numeral (here, “IIII” for April).


  1 2 3


About Norma Buchanan

Norma Buchanan is the executive editor of WatchTime magazine. She has been a reporter and editor for 30 years and has specialized in writing about watches and the watch industry for 18 years. She is also the author of "The Watch Buff's Book of Trivia."


  1. Stuart says:

    Nice but not my favourite Rolex.

  2. john landy says:

    This watch was designed by a gentleman while sitting under the ugly tree,much like every Rolex watch ever made.What about some genuine creativity. John Landy

  3. T. says:

    Innovative? Yes. Ugly & overpriced? Yes. Sky Dweller is another model that the market accepted lukewarmly. It seems that Rolex has lost its knack with certain lines.

  4. Wiliam Murchison says:

    Seriously considering the yellow gold model of Sky Dweller. Love the watch and its features but already have two Rolex watches recently purchased. Date Just II looks a lot like the Sky Dweller, even to the Champaign dial. We\'ll see...

  5. Tony says:

    The case is 42 mm in diameter and water resistant to 100 meters.
    WRONG! water PROOF....***

  6. Watchmen Watches says:

    We agree that the Rolex Sky Dweller is the most intricate and amazingly innovative automatic winding watch in the marketplace today!

  7. james says:


    • Art says:

      I love my yellow gold model. It has become one of my favorite time pieces.

  8. Anand says:

    If only rolex had not overlaped the lower numerals with the 24hr disc this watch would have been perfect.

    • Bill says:

      I agree with Anand.

      • Chris Malburg says:

        I also agree with Anand. With the additional comment that it looks strikingly similar to the Date Just. They must be thinking what works for one model will work for another. --Chris

  9. Coert Welman says:

    After the Explorer II, this is probably the best looking Rolex out there. Love the white gold version. If only I had enough time (read: money).

Leave a comment