How to Tell Time with Your Apple Watch

By Marc Saltzman

“High-quality watches have long been defined by their ability to keep unfailingly accurate time, and Apple Watch is no exception,” writes Apple on its website for Apple Watch. “In conjunction with your iPhone, it keeps time within 50 milliseconds (ms) of the definitive global time standard.”

What does that mean exactly?

Similar to other Apple devices that show the time — an iPhone, an iPad, and Mac computers — Apple Watch (through your iPhone) can tap into Network Time Protocol (NTP) time servers, such as those operated by the U.S. Naval Observatory, to automatically retrieve the correct time and time zone from the global time standard (including such information as whether daylight saving time is active).

Any transmission delay from NTP servers is still within 50 milliseconds of accuracy; therefore, Apple Watch is a timepiece you can rely on and with the “same precision found in GPS satellites,” Apple says on its website. “Apple Watch is first and foremost an incredibly accurate timepiece. It does everything a watch should, but in ways no other watch ever has.”

Because Apple Watch offers ten built-in watch faces — including Solar, time accuracy is important, particularly for a watch face that allows you to see when the sun rises and sets. You can also set certain complications to show on your watch face — such as an alarm, a world clock, and calendar appointments — and some of them also depend on time accuracy.

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A number of time-related resources are available online for those who want a closer look at different ways to measure time: