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Week number different from Google Calendar

the week number in the Google Calendar extension seems to be incorrect. At the moment, it says that we're in week 7, though, it is week 6.
I just read a post you wrote last year about this same bug, but it seems not be resolved. I am in version 19.0.8
Thank you 


  • edited February 2016
    :( This week number calculation seems very complicated, if you can figure the function that can calculate it then let me know this is the API i'm using http://fullcalendar.io/docs/display/weekNumberCalculation/
  • Hi Jason,

    why not adding in the settings a parameter to adjust week number : +1,+2,+3 ... or -1,-2,-3... ? In my case, my country is France, my current time zone is Paris and my language is english :)
  • if I set the language to french (fr), the first week starts the 4th january, but for english language, the first week starts the 27th because of the 1st which is the friday
  • Unfortuneatly it's not the same simple, here's all the little differences including by local I believe https://en.wikipedia.org/wiki/ISO_8601#Week_dates
  • Maybe the setting of the language for the fullcalender api did not work proper?
    I would expect if I change the language of my browser the week numbering would also change if you configured it to use the local configuration.
  • Hi Sacha, thank you for your reply. My case is a little bit specific : my OS is in french, as well as my browser. 
    But, in my Gmail (GoogleApps) account,  the language is english (UK), the time zone is Paris/France. What a mess ! :)
  • Could you solve this? The problem could be that week numbers depend on which day the year starts and so a week could belong to both years.

    Also, kind of related, I have enabled a calendar with week numbers on my g calendar but I don't see on the menu. However, I see it on the options tab.

  • @maximiliano.rodríguez

    I have deliberately hidden the "week number calendar" and "weather calendar" and other "gadget" calendars since they are not used in my extension.

    As for the week numbers - it's just too complicated and until someone can help he write the formula for the API mentioned above then i'm going to leave it as is.
  • @jason.savard I recently noticed this also and thought the problem was with the other program I was using... the Calendar and Countdown extension (which I'm using to display the ordinal date).  Basically the confusion is because it appears you are using the "local" option and others are using the ISO 8601 format.  Since the local option varies, I think the best thing for all would be if you would just use the ISO 8601 format and change Display Week numbers to Display ISO 8601 Week numbers.  Most people aren't aware that there is even a standard on this... and when they do, they'll just use it.  The important thing is to remain consistent between applications, and the easiest way to do it is for everyone to just use the same standard - and as I mentioned above just annotate it so people understand what is going on.
  • From your comment above, all it appears you need to do to implement this is to switch from "local" to "ISO".  Then under options, it would be good to change the verbiage next to the checkbox from "Show week numbers" to "Show ISO8601 week numbers" - that way, people clearly understand what they will be getting.  Then your week numbers will match those used on Google Calendar and other extensions.
  • @gerald.cox

    In the next update v19.1.2 (not 19.1.1 because it's already rolling out)
    I will add the week number calculation option of "local" or "ISO"

    Note: That I think the actual issue might be related to the fact that in Google Calendar the week number is marked on the Monday , but in my calendar it's labelled to the left of the weekdays.
  • edited May 2016
    Great news... I think that will eliminate the confusion.  The ISO 8601 definition for week 01 is the week with the years first Thursday in it... so on your calendar, week 1 of 2016 actually is starting on Sunday 27-December or Monday 28-December, depending on how you have configured the first day of the week.  In the ISO format the 1st week of 2016 starts on Monday, 4-January (because the 1st Thursday falls on Thursday, 7-January).  This is why the counts are off, not because of where they are labeled.  I would suggest that since you are giving the option, you make the default the ISO version - since that is what other programs seem to have done.  That way when people turn it on, it will automatically match with the Google Calendar version and keep people from filing bug reports.  (***Edited to correct ISO8601 definition).
  • @gerald.cox

    ok excellent advise, here's a screenshot with ISO calculations for the next version hopefully this is correct...

  • Hummmmm... I think I see what you were talking about... can you set your options to start the week on Monday and then run again.  Sunday, May 1st is the last day of week 17... Week 18 begins on Monday, May 2nd.  If it still is showing week 17 after you make that change, something else is wrong.  
  • @gerald.cox

    ISO with Monday start of the week ...

  • Yes, that is correct!  If people are setting their week to start on Saturday or Sunday, I'm not sure what you can really do about that.  It's just going to give them misleading results.  If you're using ISO week numbers you "should" already know that means the week starts on Monday and have your settings adjusted accordingly.  Thanks for fixing this.
  • Great job Jason and thank you Gerald for helping !
    Jason, can you add a background color in the week number color to make it easier to read. Sometimes, rhe week number make confusion with day number. 

    Thank you
  • another good suggestion, thanks Toufik, this change will go live in v19.1.2
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