PolyClock requests the following permissions from the Android system. Tap on any of the permissions – or just scroll down – for a detailed explanation of exactly what PolyClock is doing with each.

Required to display the Local city and zone.
Required to search for time zones and download satellite imagery.
Used to store various images for faster operation.
Required to apply time zones from PolyClock to the device.
Required to re-establish alarms after device reboot.
Used to vibrate the device when an alarm sounds.


One of PolyClock’s headline features is the Local Clock, which follows your current location and always shows the correct local time. It will also display sunrise and sunset information, as well as showing your location on the map and globe. Optionally, it can even automatically correct your device’s internal time zone setting when it’s wrong.

All of these functions require PolyClock to know roughly where on Earth you are, and to do that, it requires your approximate (or coarse) location. This permission lets it acquire that location quickly, and with little battery use, from your network provider.


Ordinarily, PolyClock is perfectly happy to use your approximate (network-based) location; the low accuracy is more than sufficient for the app’s purposes. See the previous permission for more details on this.

However, a problem arises when you don’t have network coverage, or when you’re roaming on a network which doesn’t provide location services. The app still needs your location, and GPS is the only other (automated) alternative. For people who use the app in remote areas - say, when camping, or traveling overseas – this is the only way the app can get their location.

So, the app requires the GPS permission. But it doesn’t actually need your precise location, and you are free to turn off the GPS interface, either within the app (see the Local Clock settings), or system-wide on your device. You’ll just be limited to network-based location services.

Finally, rest assured that the app won’t power on your GPS if you’ve turned it off at the device level. No app can do that unless you’ve rooted your device – and even then, PolyClock won’t.


PolyClock has two functions which require internet access.

First is time zone search; by querying internet search services, the app can look up the time zone and location for virtually any city, town, or other generally-known placename. This allows you to add just about anyplace to the displayed clock list, and greatly enhances the versatility of the app.

Does this mean that PolyClock requires an internet connection to function? Not at all! The app includes an internal database containing several thousand of the largest cities on Earth; without an internet connection you can still add any of these cities to your list. You can also add arbitrary cities (not in the internal database) without looking them up; you’ll just need to select their time zones manually.

Second, version 3 of PolyClock added a satellite option for the map and globe. The satellite imagery is relatively large, however, so to keep the size of the app down, it’s only downloaded on demand. This occurs once, when you first select the Satellite option; thereafter, the imagery is stored on your device, and won’t need to be re-downloaded.


The exact wording of this permission varies by device, but it means the same thing: the app has the ability to read and write your device’s user data storage, be that an SD card, USB drive, or internal storage.

This permission is primarily needed for PolyClock's backup and restore functionality. In order to read and write backup files, the app needs authorization to access your device's storage, where those files are usually placed.

PolyClock also uses this permission to increase the speed (and decrease the battery usage) of its day-to-day operations. It’s a graphically-intensive app - from the map and globe to the day/night backgrounds of the clock rows and widgets – and creating these graphics can be a load on the system. So, the app goes to great lengths to not create graphics more than it has to; instead, it saves copies of these graphics for future use. This is best done on your device’s user storage, so PolyClock needs permission to do so.

The app does its best to manage this storage use, and not use too much. If you want to delete these files manually, you can do so from your device’s system settings, under Applications > Manage Applications > PolyClock > Clear Data. These files will also be deleted automatically by the system if you ever uninstall PolyClock.


Another key function of PolyClock is its ability to correct your device’s system time zone, and to do so, the app needs this permission. Unlike many Android permissions – cryptically-named, ill-described, or both – this one does exactly what it sounds like, nothing more, nothing less.


PolyClock features time-zone-specific alarms which you can set. Unfortunately, Android doesn’t maintain alarms when the device reboots; such alarms are essentially "forgotten" by the system when you shut down your device. The solution is re-set the alarms when the device powers back up – and to do so, PolyClock needs to start when your device boots.

The good news is that the process of reestablishing alarms takes a small fraction of a second, and so adds minimal time to your device’s boot-up lag. You may also be concerned to see a system monitor showing PolyClock as "still running" after the boot has completed; this is normal, and simply means that the system is keeping PolyClock around in case you run it manually. If your system needs the resources it’s holding, this "dormant" PolyClock will be automatically removed. It’s just how Android works.


PolyClock’s time-zone-specific alarms include an option to vibrate the device when the alarm fires (on compatible hardware). This is useful in noisy environments, where you might not hear the alarm sound, or sometimes in quiet situations, where the alarm sound would be too intrusive.

If you’re concerned about your device vibrating, be aware that you can also turn it off device-wide, in the system settings – a preference which PolyClock will honor.