The Zen of Time Zones

If you travel any distance, or have contact with people far away, you already know that it's not the same time everywhere. But the more time zones you deal with, or the further away they are, the more confusing it becomes. How many hours earlier is Paris than here? Or is it later – I can never remember. What about Phoenix this time of year – is this when it's on Mountain time, or Pacific? And don't even get me started on the International Date Line!

PolyClock was designed and built from the ground up to provide these answers, easily and intuitively. Here's how:

Places are More Important than Time Zones

One of the basic principles underlying PolyClock is to show the time in specific places rather than generic zones. Because the truth is, a time zone is really just a means to an end: it's a group of places where all the clocks read the same. But if you want to phone John in Honolulu or Paula in London, you don't really care what zone they're in – if they started Daylight Saving last weekend or not – you just want to know what time it is there. Is he at work? Is she awake?

screenshot of polyclock on nexus 1

A simple glance at PolyClock's main screen tells you in an instant. London's good, Honolulu's a bit early. And chatting with Karen in Sydney is right out – it's after midnight.

Meaning it's tomorrow there, of course. PolyClock shows you that as well, incorporating a simple color code of turquoise = tomorrow, yellow = yesterday.

Integrated Map and Globe

An even more basic question than "what time is it?" is "is it day or night?" Because the sun can only shine on one side of the earth at a time, of course, it's always daylight on one half of the planet and night on the other. Somewhere, the sun is rising, and somewhere else, it's setting, right now.

This is intrinsically why we have time zones: they're an attempt to standardize this basic natural condition. So it follows that an excellent way to visualize time zones is on a map or globe, correlated to the day and night areas of the earth. This why you'll find a map and globe to be central to PolyClock's design: they let you see exactly the current global distribution of day and night. Touch any city on your list to select it; its location will be highlighted (the yellow spot on London above), along with the extent of its true, current time zone (the lighter strip on the globe: it's 4:40 PM in that entire area). Over the course of the year, you'll notice that most zones change shape, as Daylight Saving and Summer Time begin and end. And naturally, the day/night pattern will shift with the seasons as well.

If you'd rather see less of the map or globe and more of your clock list, that's fine too. Just slide its "drawer" shut, and open it again when you're ready for another look.

screenshot of polyclock on nexus 1

Daylight Clock Technology

Bringing the global day/night cycle back home to a specific place is the job of PolyClock's exclusive daylight clock technology. This comes in two forms; with a digital PolyClock (at left), it's a horizontal band divided into two colors, sky blue for day and black for night. Twilight is the gradient between the two, and the current time is indicated by the thin white "now" line down the middle of the screen. So at a glance, you can immediately see that it's the middle of the day in New York, the middle of the night in Sydney.

These daylight bands are correlated with each other – naturally – and with the time scale at the top of the screen, which lets you nail down their specifics. The sun will be rising in Honolulu in about an hour, setting here in London in about four, then rising in Sydney another hour after that. Want more specifics? Double-tap any clock row to open its Details page.

Finally, the selected clock's band is also correlated with the map underneath. Note that New York's map dot is directly beneath the "now" line – then see that New York's daylight band is exactly the width of the daylight on the map to the east and west of NYC. That's the global day/night cycle, in a nutshell. And here's a tip: see that grid on the map? Those lines are an hour apart.

Turn your phone sideways and PolyClock automatically switches to analog clocks, as shown at the top of this page. These are still daylight clocks, though they don't correlate quite as nicely as the analog bands. Rather than having a "now" line, the day/night pattern is tied to the clock's hour hand. If the hour hand is in the blue, it's daylight, and black means night. Everything else works just the same.

The Local Clock

Of course, the place whose time you're probably most interested in is where you are, right now. That's why PolyClock defaults to always showing a Local clock, set to the time zone from your device, and using the network or GPS to establish your location for the daylight clock. As you move from place to place, the Local clock will always track your current time, showing you the same level of detail as for anywhere else.

If you travel a lot, and you find that your phone doesn't always pick up the current time zone along the way, you can also set PolyClock up to automatically correct your Local zone. Or you can turn the Local clock off completely, either by tapping Menu > Delete, or from the Settings screen.