When you first set up your Apple Watch, you may or may not have a few world clocks on it. You can change the world clocks on your Apple Watch, but you'll need to use your iPhone to do it.

Adding, subtracting, and changing world clocks on the Apple Watch would seem like it would be fairly intuitive, but it is not. In fact, in order to do anything with world clocks on your Watch, you must use your iPhone's Clock app.

Here is the World Clock app on the Apple Watch. In this case, the only two clocks available are Cupertino and New York. Your Watch may vary.

So, let's go ahead and change our world clocks so they are then reflected on your Apple Watch's world clock app.

First, open the iPhone's clock app and tap open the World Clock tab.

Once you've opened up the World Clock settings, tap "Edit" to access your world clocks. Next to each clock a "-" symbol will appear. To remove a clock, tap that symbol.

You will need to confirm your intentions by tapping the "Delete" button that appears to the right of each world clock city. It will then be deleted.

Now, tap the "+" symbol in the upper-right corner and you can pick your city or cities.

Now you see that we've added a few more cities to our world clocks on our iPhone.

Now, we'll go back to our Apple Watch, and all our new clocks should be reflected in our World Clock app. For example, you see when we tap open Brasília, it shows us all the pertinent information about that city.

So, there you have it. Now you can add any cities you want to your Apple Watch and quickly check the time wherever you are without having to whip out your iPhone (unless you want to make changes, of course).