he history of Patek Philippe’s World Time watches dates back to the 1930s. Based on an invention by master watchmaker Louis Cottier of Geneva, it quickly established a reputation as both a prestigious and a useful watch, at a time when the first transatlantic flights were taking off and intercontinental travel was becoming more commonplace. Its basic operating principle is as ingenious as it is simple to use: two mobile discs – the cities disc representing the 24 time zones, and the 24-hour disc – make it possible to tell the time in each of the 24 time zones simultaneously and at all times. The hour and minute hands in the centre indicate the traveller’s local time, defined as the time zone positioned at 12 o’clock.

The enduring success of Patek Philippe’s World Time watch is due not only to its practical qualities as a timekeeping instrument serving the specific needs of the traveller, but also to its intrinsic aesthetic qualities, such as its dial centres decorated with cloisonné Grand Feu enamel world maps or handcrafted guilloché motifs. In the decades since 1937 Patek Philippe has created numerous variations of this complication, which has become a hallmark of some of the Geneva manufacture’s most recognisable and sought-after watches.

The quest for the ultimate in functional ergonomics

One of Patek Philippe’s longstanding areas of innovation is the obsessive pursuit of the greatest possible simplicity of use and daily utility for the complications it offers. In 2000, Patek Philippe succeeded in significantly improving the functional ergonomics of its World Time Ref. 5110. The first models, released from 1937 onwards, featured a display on a fixed disc and a rotating bezel. The traveller could change the position of the bezel, set the local time and also read the time in other time zones. In the 1950s another system was introduced with two crowns, one to move the reference city to 12 o’clock and the other to set the hour hand to local time. Patented in 1999, the latest exclusive mechanism allows the traveller to simultaneously adjust all the displays – city disc, 24-hour disc and central hour hand – by pressing (in one-hour increments) a single pusher located on the side of the case at 10 o’clock, when changing time zones. This does not affect the precision of the minutes, which remain identical in all time zones (with the very rare exceptions of 45, 30 or even 15 minutes).

In 2014, Patek Philippe added a new indication to the World Time watch: a moon phase, which can also be considered “universal” because the moon is in the same phase regardless of one’s location on Earth, although the view is inverted (either a C or a D shape) depending on whether it is being observed from the northern or southern hemisphere. In this Patek Philippe World Time Moon (Ref. 5575, 175th anniversary limited series) a large hyper-realistic metallised moon set on discs of extremely thin mineral glass is displayed in the centre of the dial. It’s both universal and poetic.

Two years later, in 2016, Patek Philippe unveiled the World Time Chronograph Reference 5930 featuring a very rare combination of complications inspired by a unique piece dating from 1940 (which can be admired at the Patek Philippe Museum in Geneva). Combining an automatic column-wheel chronograph movement with a vertical clutch with the World Time mechanism required extensive adaptation, relocating axes, modifying spacings and reconstructing bridges. And there was a further interesting detail: thanks to the presence of a vertical clutch, the chronograph seconds hand could also be used as a running second without affecting the watch’s precision and power reserve.

The following year, in 2017, on the occasion of its Grand Exhibition in New York, Patek Philippe presented a novel limited edition World Time watch. It was the first timepiece with a minute repeater that, unlike every other minute repeater that continued to chime home time regardless of local time, was mechanically coordinated with local time. This World Time Minute Repeater entered the current collection in 2018 under the reference 5531 R, with an automatic movement. Although it is beyond the scope of this article to explore the technical details of this spectacularly complex and sonorous achievement, suffice it to say that the mechanical coupling between the world time display with its rotating city and 24-hour discs, and the chiming mechanism, with the minute, quarter and hour snails that drive it, forced Patek Philippe’s engineers to completely overhaul the movement architecture. This innovative construction became the subject of a patent application, as did the novel approach of attaching the gongs to the case middle rather than to the movement plate, in order to improve the volume and thus the acoustic comfort of the traveller.

The conquest of local date

The year 2024 marks a new milestone in what we might, with some justification, call the epic saga of Patek Philippe’s World Time watches. After being introduced as an exclusive limited edition reserved for the Japanese market at the Watch Art exhibition in Tokyo in June 2023, Patek Philippe is adding the World Time Reference 5330G-001 to its current collection. This is the first World Time watch with a date that is indexed to local time.

Originally produced in a limited series of 300 for the “Watch Art” exhibition that took place in Tokyo in 2023, this Ref. 5330 is Patek Philippe’s first World Time to include a local date display.

Yes – a date. Although this common function is usually quite simple to implement, automatically synchronising the date with the local time displayed on a world time mechanism is a challenge of a completely different magnitude. The technical difficulty is twofold. Coordinating the date change, which always takes place at midnight regardless of the time zone, with local time, which could go forwards or backwards during any given trip, means that the midnight jump must also be capable of going either forwards or backwards, depending on the selected time zone. But the technical challenges do not end there.

The date equation becomes even more complicated when you realise that the date linked to local time has to change not only when the time ticks past midnight and into the next day, but also when crossing – in either direction – the date line that runs through the middle of the Pacific, regardless of the time of crossing, with a single exception: between 11 am and 12 am Greenwich Mean Time the entire planet is on the same date at the precise moment when it is midnight on the Pacific date line – the 180th meridian – which passes between Auckland and Midway, at the exact antipodes of the Greenwich meridian, or 0°.

Despite its great complexity, the 240 HU C micro-rotor calibre that equips the World Time Ref. 5330 is only 4.58 mm deep. This allows it to be housed in an elegantly slim 40 mm diameter case with a total height of 11.57 mm.

For the user, this exclusive and innovative function of displaying local time and date is both useful and simple to use: each press on the pusher at 10 o’clock adjusts the city disc, the 24-hour disc, the local time central hands and, if necessary, the local date, simultaneously. But its design, technical development and quality control required all the intellectual resources and know-how at the manufacture’s disposal. Simply put, the local time date mechanism is governed by a patented central differential system that includes two concentric gears or stars. One of these stars has 62 teeth, the other 31. When the larger outer star rotates clockwise, the date hand advances one notch clockwise at midnight. When the smaller inner star rotates clockwise, the date hand moves backwards in an anti-clockwise direction. Thanks to the differential, when the two gears rotate together, i.e. with a simultaneous forward and backward motion, the action is cancelled out and the date hand remains on the same date.

2000 – WORLD TIME REF. 5110 – 37 mm CALIBRE 240 HU: This is the first Patek Philippe World Time watch to feature the highly innovative 240 HU calibre, an automatic micro-rotor movement measuring just 3.8 mm deep. The patented mechanism enables the wearer to simultaneously adjust the city disc and the 24-hour disc with one press of a pusher.

2014 – WORLD TIME MOON REF. 5575 – 39.8 mm CALIBRE 240 HU LU: To celebrate its 175th anniversary in 2014, the Geneva manufacture introduced two limited-edition World Time Moon watches featuring an extremely realistic moon phase indication in the centre of the dial. The men’s model, limited to 1,300 pieces, is in white gold, while the smaller women’s model in rose gold comes in a limited run of 450.

2016 – WORLD TIME CHRONOGRAPH REF. 5930 39.5 mm – CALIBRE CH28-520 HU: Integrating two sophisticated complications, such as a World Time display and chronograph functions, presents a significant challenge. Prior to the introduction of the Ref. 5930, this had been achieved only once before, in a Patek Philippe watch from the 1940s (Ref. 1416-1 HU).

2018 – WORLD TIME MINUTE REPEATER REF. 5531 G – 40.2 mm CALIBRE R 27 HU: Following an initial limited series produced for “The Art of Watches” in New York in 2017, Patek Philippe introduced the World Time Minute Repeater into its regular collections for the first time. This exceptional watch is equipped with a minute repeater that chimes the local time of the city positioned at 12 o’clock.

In this way the World Time Date is able to handle any situation created by changing time zones and crossing the international date line. The date adjustments needed at the end of every 30-day month or in February are executed via a discreet corrector located at 8 o’clock.

The date is shown on a slender central hand with a red tab that points to a 1-31 scale printed on the periphery of the dial. A striking feature of this hand is that it is made of glass, i.e. it’s transparent, so as not to impair the legibility of the other information. It is the subject of two patents: one for the glass lacquering process – the red tab – and the other for the way the glass hand is attached to the metal shaft that drives it.

Elegance and refinement

Despite its complexity, the new 240 HU C automatic calibre with micro-rotor that powers the World Time is only 4.58 mm deep, allowing it to be housed in a slim and elegant white gold case (40 mm diameter with a total thickness of 11.57 mm). The three-sided white gold dauphine hands (coated with Super-LumiNova for better night-time visibility) stand out against a deep blue opaline dial with a discreet geometric guilloché motif in the centre. On the 24-hour disc, noon and midnight are indicated by a sun and moon respectively, while on the city disc the Greenwich meridian (London) is marked with a red dot and, at the antipodes, another red dot indicates the international date line that passes between Auckland and Midway.

Mounted on a hand-stitched denim effect blue calfskin strap with a two-pronged Calatrava white gold folding clasp, the “global” World Time with local date is ready for its world tour.