Re: Commercial Concalendar

On Mon, Sep 27, 2004 at 03:31:16PM -0400, Jeffrey Henning wrote:
> Alas, when we customized our software for them, they neglected to inform us
> that every four years they need to insert a leap week:  Week 1E!  Otherwise
> their project year gets out of sync with their fiscal year.  So we need to
> modify our validation to handle this leap week.
Are you sure it's every four years?  A leap week every four years is too
often; to keep in synch with the tropical year leap weeks need to
happen between 5 and 6 years apart.

I would guess that under the covers they are using the ISO calendar,
which just numbers the weeks 1-52 or 53 without breaking it up into any
sort of "month".   The leap-week schedule is somewhat uneven because
it's actually based on the Gregorian calendar: week 1 is always the
first week that contains at least 4 days in January (no more than 3 in
December).  There is a leap year (a year with a "week 53") whenever
there are 53 instead of 52 weeks between consecutive "week 1"s.

-Marcos