Possible TZ Data Errors with every 1st / 2nd / 3rd Xday of the month

Dr Hingston dr.hingston at paradise.net.nz
Wed May 31 08:31:05 UTC 2006

Dear List  Members

Woops, seems I got the address wrong, my apologies!  I hope this is better!


Rule Chile 1999 max - Oct Sun>=9 4:00u 1:00 S
Rule Chile 2000 max - Mar Sun>=9 3:00u 0 -

The expression Sun>=9 from the above rules would appear to me to be incorrect, as it suggests the third Sunday in some years.   e.g. October this year.


http://www.twinsun.com/tz/tz-link.ht (!)

which lists:


Summary:  Supreme Decree Number 1,489 (6 October 1970) - This law, enacted during the presidency of Eduardo Frei Montalva, declared that Daylight Saving Time will advance clocks by one hour, beginning the second Saturday of October, and ending the second Saturday of March. Chilean time is administered by the Chilean Navy's Hydrographic and Oceanographic Service (SHOA).

On discussion with the Chilean Consulate the above is confirmed, and time for changeover is midnight Saturday (I take to mean 00:00 Sunday)

It would seem to be correct, to me, if it were stated as Sun>=8.

Similarly, if I am correct, then there are quite a number of other instances in the database where the expression Sun>=9 perhaps might be more correctly stated as Sun>=8?

Extrapolating further, if I may, some of the other instances may also be incorrect, e.g. Sun>=16 etc.

Some examples:

Rule ChileAQ 1966 1997 - Oct Sun>=9 0:00 1:00 S
Rule Belize 1919 1943 - Feb Sun>=9 0:00 0 S
Rule Falk 1985 2000 - Sep Sun>=9 0:00 1:00 S
Rule Falk 1986 2000 - Apr Sun>=16 0:00 0 -
Rule GB-Eire 1945 1946 - Oct Sun>=2 2:00s 0 GMT
Rule GB-Eire 1946 only - Apr Sun>=9 2:00s 1:00 BST

Where a week day is stipulated as the Xth day of the month then I believe the correct references should be >=1, >=8, >= 15, >= 22 etc.  Therefore I question other numbers, of course they may be correct, however this does seem to suggest careful scrutiny of those numbers is indicated.

I'd be grateful for list consideration and comment please.

Kind regards
David Hingston 

-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://mm.icann.org/pipermail/tz/attachments/20060531/edf8807c/attachment-0001.html 

More information about the tz mailing list