Stack Exchange sites use ISO-8601 date formats, and if they don't, it's considered a bug if the site uses the date format commonly used in the USA. It also uses the 24 hour clock, and it's again considered a bug if this isn't the case.

So the SE sites don't use the date and time formats commonly used in the USA (where SE Inc. resides) and even shows times in UTC, which is a very good thing, considering the international and culturally diverse audience of the sites (well, only second to individually configurable preferences I guess).

Unfortunately, what is not considered are week boundaries defined in the same standard, i.e. what day of the week is considered to be the first weekday.

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These are implicitly shown in the Users tab, and explicitly in the User Reputation Leagues. Today I earned 130 rep, and that's my total for "this week":

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In many countries across the world, and in the mentioned international standard ISO-8601, Monday is the first day of the week, rather than sunday. It appears that only the USA, Canada, Japan and Israel consider Sunday to be the first day of the week.

Now we have

  • International standard based date format, rather than mm/dd/yyy commonly used in the US
  • International standard based time format, rather than the AM/PM used in the US
  • Week boundaries as only used in the US, Canada, Japan and Israel.

This is inconsistent and should be fixed.

  • Why do we even need week boundaries? Why can't "this week" be "between right now and seven days ago"?
    – Toomai
    Dec 2, 2011 at 20:34
  • @Toomai At least the reputation leagues. The users list might work without boundaries at year/month/week. It's a good question though, on /review it actually makes it more difficult. Currently, on sundays, the week category is totally useless. Dec 2, 2011 at 20:36
  • 1
    You are saying SO uses ISO-8601 dates, when it really doesn't. "Nov 27 at 15:54" is not ISO-8601. But I agree with your sentiment. Dec 2, 2011 at 20:53
  • @NullUserExceptionอ_อ Check the tooltip with the canonical date representation. Just like 32 secs ago, it's just a more accessible label. As soon as you want to get the exact date and time (especially for yesterday, 5 min ago, etc.), it's ISO. Dec 2, 2011 at 20:55
  • 1
    My sentiment is similar to Josh's - I can't help but accept that this makes sense, but I don't really like it. (I'm very fond of treating Sunday as the week's first day.)
    – Pekka
    Dec 2, 2011 at 21:05
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    @Pekka In that case, it might comfort you that its not very visible. It's the view options for the users list, the user leagues, and the review pages. I think that's it. Dec 2, 2011 at 21:12

1 Answer 1


I reluctantly had to upvote your question.

I really don't like this idea. To me, Sunday has always been the "first day" of the week, and most calendars will display this way. However, I am in the USA, and I had to recognize that I am being stubborn.

The way it is now is inconsistent as you say, and it doesn't make any sense to keep it this way. Also, it shouldn't really have any effect on reputation leagues... it may change who is the leader of a given week, but every week will still contain both a Sunday and a Saturday, so it will end up being a wash.

Wikipedia and the ISO standard clearly state that Monday is the first day of the week...

  • 1
    Italian calendar shows Monday as first day of the week.
    – apaderno
    Sep 25, 2012 at 3:53

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