Clock is off by a couple minutes

[SoAnyway]

I've been noticing that my iMac's clock is off by a couple minutes. I'm running 10.9.1 and have my Mac automatically sync with Apple's for time.

When I check the time on my iPhone, it's different from the time on my iMac and have determined that it's the iMac that's off by a couple minutes.

It's not that big of a deal but has anyone else noticed this lately?

 

[explode90]

Hmm, mine are identical. Does your iPhone set time automatically too?

 

[chown33]

View a reliable time source, such as the US Naval Observatory:
http://tycho.usno.navy.mil/what.html

That page displays a digital clock in UTC (JavaScript must be enabled).

Compare the mins:secs to the time shown by your Mac and your phone.


In my experience, the Mac's time is well within 1 sec of USNO displayed time, if the Mac has recently been synced automatically (Date & TIme pane in System Preferences).

When I check the time on my iPhone, it's different from the time on my iMac and have determined that it's the iMac that's off by a couple minutes.

Please explain exactly how you determined this.

 

[Alrescha]

I have found that some AT&T time sources/towers are notoriously bad (as compared to the distributed time servers used by my company's infrastructure).

A.

 

[SoAnyway]

Hmm, mine are identical. Does your iPhone set time automatically too?

Yeah my iPhone does sync the time automatically.

View a reliable time source, such as the US Naval Observatory:
http://tycho.usno.navy.mil/what.html

That page displays a digital clock in UTC (JavaScript must be enabled).

Compare the mins:secs to the time shown by your Mac and your phone.


In my experience, the Mac's time is well within 1 sec of USNO displayed time, if the Mac has recently been synced automatically (Date & TIme pane in System Preferences).



Please explain exactly how you determined this.

I first noticed the time was off on my Mac from an app that I use daily which also displays the time (hours, minutes, seconds). I originally thought it might have been the app but then I checked my iPhone and it was displaying the same time as the app. So I opened up the clock app on my iPhone and displayed the time in house, minutes, seconds on the Mac and the Mac was ahead by a couple of minutes.

 

[ScoobyMcDoo]

In the terminal type the command:

ntpq -p

and post the results.

 

[SoAnyway]

I recently gave my Mac a restart and the clock is back to normal, at least for now. I'll keep an eye on it every so often and see if it's ever off again.

By the way, I weeks and sometimes months without restarting my Mac, could not restarting contribute to the clock being off?

----------

In the terminal type the command:

ntpq -p

and post the results.

I don't know if it will help now as the clock is back in sync.

 

[Alrescha]

By the way, I weeks and sometimes months without restarting my Mac, could not restarting contribute to the clock being off?

It should not. The purpose of ntp is to keep the time synchronized continuously.

A.

ps: I have seen ntp get stupid after waking from sleep. Sometimes it recovers, sometimes not.