When you mouseover a "3 hours ago" time, you get the exact timestamp.

Here's an example of what I get -- the code says:

<span title="2009-07-20 23:12:37Z" class="relativetime">Jul 20 at 23:12</span>

And the tooltip says:

"2009-07-20 23:12:37Z"

Does this mean the code doesn't know what my timezone is? (NZST, as it happens) If so, what timezone is that time in?

EDIT: Wiki says:

The UTC time zone is sometimes denoted by the letter Z – a reference to the equivalent nautical time zone (GMT), which has been denoted by a Z since about 1950. The letter also refers to the "zone description" of zero hours, which has been used since 1920 (see time zone history). Since the NATO phonetic alphabet and amateur radio word for Z is "Zulu", UTC is sometimes known as Zulu time. This is especially true in aviation, where Zulu is the universal standard. This ensures all pilots regardless of location are using the same 24-hour clock, thus avoiding confusion when flying between time zones.

All I can say is: "That's news to me". Is Z really more common than UTC or GMT amongst people who don't fly planes or steer boats?

  • 3
    Depends on who you talk to and what ops you're involved in.
    – random
    Commented Aug 21, 2009 at 5:48
  • I think one category can be added to "people who don't fly planes or steer boats": part of the IT community. But now that many non-IT and non-technical sites exist, maybe UTC would indeed be better. And UTC is also used in other places on these sites.
    – Arjan
    Commented Jan 14, 2012 at 15:04

3 Answers 3


The Z on the end of the time implies Zulu or UTC.

See here.

  • 1
    More precisely this is the standard notation in ISO 8601. Commented Sep 25, 2012 at 3:04

As already pointed out, Z means UTC. For details, check these:

  • http://en.wikipedia.org/wiki/ISO%5F8601#UTC
  • http://www.timeanddate.com/library/abbreviations/timezones/military/z.html

However, I think 2009-07-20 23:12:37 UTC would better than 2009-07-20 23:12:37Z; it's slightly more readable and would cause less confusion (like in this question, and here and here!). (And it's not like we're running out of space in the tooltip, as Shog9 aptly noted earlier.) Extremely small thing obviously, but probably very cheap to implement too? :-)

Also, I tend to agree with the suggestion by cletus that (optionally!) using a user-selected local timezone for all timestamps might be somewhat more useful. But well, UTC only isn't too bad, especially as recent times are shown along the lines of "6 hours ago" anyway.

  • 2
    Ah, but looking at meta.stackexchange.com/questions/14684/…, it might be unlikely they want to change it again (especially as "2009-07-20 23:12:37 UTC" strictly speaking wouldn't be ISO 8601?)
    – Jonik
    Commented Oct 14, 2009 at 14:02

I've never seen an option anywhere on SOFU to set your timezone, so I guess - no.

That said, most of the times are "20 minutes ago" which makes it redundant for viewing the most common pages (front page, and questions on the front page), and if they're older than that it's the date that's more important than the time...

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