Clocks out of sync

Question

Clocks out of sync

The clock on my iPhone 4 is about 30 seconds out of sync with my Macs (running OSX 10.6.6).

On the iPhone Settings/General/Date & Time I have 'Set Automatically' set to On.

On the Mac in Sys Prefs/Date and Time/Date & Time tab I have 'Set date and time automatically' checked and in the adjacent drop down menu 'Apple Europe' selected.
In the Time Zone tab I have 'set time zone automatically using current location' checked and it has successfully found Greenwich Mean Time, London. UK. In the Clock tab I have digital 24 hr clock.

The Mac Book Pro and the Mac Pro are in sync but the iPhone is about 30 seconds behind them.

I have good wired and wireless broadband connections and iPhone connects OK to wireless.

Any suggestions?
thanks
Pete

Message was edited by: Peter Whitaker

Mac Pro / Mac Book Pro 17" / iPhone 4, Mac OS X (10.6.6)

Posted on Mar 8, 2011 9:43 AM

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Answer 1

Graeme74

Level 1

10 points

Sep 7, 2017 12:25 AM in response to Peter Whitaker

I found by looking at the GMT website that it was my Mac that was wrong (by nearly two minutes). Went to try turning, 'automatic' off and on in 'date & time' preferences and as soon as I unlocked the preferences it fixed itself without even having to take the planned action. The act of simply unlocking the preferences panel caused it to check itself. Maybe a 'locked' panel locks it against automatic correction, which would be a bug.

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Answer 2

Randy Fast

Level 4

1,432 points

Mar 8, 2011 9:45 AM in response to Peter Whitaker

Don't worry about a 30 second difference. Mine is ~20 seconds fast compared to my computer.

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Answer 3

Mar 8, 2011 9:57 AM in response to Randy Fast

But I am worried !!

just kidding but.... I would be interested to know why it is out of sync

- and if there's a fix.

And it would help if it was accurate... when I'm running late etc

Pete

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Answer 4

Mar 8, 2011 10:18 AM in response to Peter Whitaker

At a guess, I would say that since you are relying on two different time servers, the servers themselves are not in exact sync (always seems to me too, that it is the cell tower time signal that is most likely to be off, don't know why that is).

I understand how it grates on you though 😉 I own several wrist watches and they, and all my clocks at home are so-called "atomic" time devices. That is, they all get their daily time signal from the National Standards radio transmitter in Ft. Collins which is synced to a cesium (? I think) clock. So my watches and my house clocks are always in sync and always correct (even automatically adjusting for daylight savings and standard time shifts) - it does irritate me when the computers (all sync'd to US Naval Observatory NTP servers) and the iPhone get out of sync with the rest of them.

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Answer 5

GLTorii

Level 1

0 points

Mar 8, 2011 1:27 PM in response to Peter Whitaker

My phone was out of sync for a while as well. Here in Brazil when Daylight Saving Time ended, my iPhone did not move back an hour automatically. It showed 1 hour ahead for a couple of days until I decided to switch the time adjustment to manual and input the right time myself. At the end of the day I remembered about it and switched back to automatic and it held the right time. I have no idea what could have happened but it is working now.

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Answer 6

djomaha

Level 1

74 points

Mar 8, 2011 1:37 PM in response to Peter Whitaker

I believe that the clock in the iPhone syncs it's time from the phone service server. I base this on experiences while traveling with the phone. While in Airplane mode, my iPhone time does not update to a new time zone. Once I turn Airplane mode off, the current time zone I'm in gets sent to my phone, presumably from the local cell phone towers. It is therefore extremely likely that any 2 servers in different locations will be off a few seconds from each other. When you are at home, your laptop is getting the time through your internet connection, and your iPhone is getting the time from your cell phone towers.

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Answer 7

paulcb

Level 6

19,245 points

Mar 8, 2011 1:45 PM in response to Peter Whitaker

The iPhone gets it's 'automatic' time from the cell tower, not wireless, thus the difference.

See p. 204... http://manuals.info.apple.com/enUS/iPhone_iOS4_UserGuide.pdf

Message was edited by: paulcb

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Answer 8

Mar 9, 2011 3:13 AM in response to paulcb

Thanks for all the informative replies.

If the cell towers are not so accurate I wonder why there is no option to sync the iPhone clock via the internet. Presumably this could be done via wi-fi or 3G depending which is available.

Also... Michael are you saying your computers are out of sync with the atomic clocks?

Pete

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Answer 9

wjosten

Level 10

95,369 points

Mar 9, 2011 3:14 AM in response to Peter Whitaker

You can get this app:

http://itunes.apple.com/us/app/precise-time/id391343043?mt=8

And, suggest Apple add that functionality here:

http://www.apple.com/feedback/iphone.html

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Answer 10

Mar 9, 2011 3:29 AM in response to wjosten

Thanks that looks cool... will investigate the app.

Meanwhile on the subject of synchronising / Atomic clocks / servers /
I found this interesting from Wikipedia:

"Coordinated Universal Time (abbreviated UTC)[1] is the time standard by which the world regulates clocks and time. Computer servers, online services and other entities that rely on having a universally accepted time use UTC for that purpose. Though there are scientific differences (explained below) between UTC and Greenwich Mean Time (GMT), in the broad sense as understood by non-specialists, GMT is the same thing as UTC.
Coordinated Universal Time is a time standard based on International Atomic Time (TAI) with leap seconds added at irregular intervals to compensate for the Earth's slowing rotation.[2] Leap seconds are used to allow UTC to closely track UT1, which is mean solar time at the Royal Observatory, Greenwich.
Since the difference between UTC and UT1 is not allowed to exceed 0.9 seconds, if high precision is not required, the general term Universal Time (UT) may be used.[3]
In casual use, when fractions of a second are not important, Greenwich Mean Time (GMT) can be considered equivalent to UTC or UT1. Saying "GMT" often implies either UTC or UT1 when used within informal or casual contexts. In technical contexts, usage of "GMT" is avoided; the unambiguous terminology "UTC" or "UT1" is preferred.[3]
Time zones around the world can be expressed as positive or negative offsets from UTC as in this list; UTC replaced GMT as the basis for the main reference time scale or civil time in various regions on 1 January 1972.[4]"

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