Question regarding America/Manaus timezone
alain.petit at oracle.com
Wed Dec 9 14:44:35 UTC 2009
[This is a resending due to issues with the email address I sent to. I apologize if you receive it in double]
Looking into some timezone information I have the following interrogation, and
I am unsure if my interpretation of the file is wrong, or if the rules are wrong...
This comes from tzdata2009s, southamerica file
The rules are
# Rule NAME FROM TO TYPE IN ON AT SAVE LETTER/S
Rule Brazil 2008 max - Oct Sun>=15 0:00 1:00 S
Rule Brazil 2008 2011 - Feb Sun>=15 0:00 0 -
Rule Brazil 2012 only - Feb Sun>=22 0:00 0 -
Rule Brazil 2013 2014 - Feb Sun>=15 0:00 0 -
# east Amazonas (AM): Boca do Acre, Jutai, Manaus, Floriano Peixoto
# The great circle line from Tabatinga to Porto Acre divides
# east from west Amazonas.
Zone America/Manaus -4:00:04 - LMT 1914
-4:00 Brazil AM%sT 1988 Sep 12
-4:00 - AMT 1993 Sep 28
-4:00 Brazil AM%sT 1994 Sep 22
-4:00 - AMT
>From what I understand from the above, America/Manaus does not observe DST ever since Sep 22, 1994.
However, looking at the Microsoft Timezone definition [Dec 2009 update]
for (GMT -4:00) Manaus [Central Brazilian Standard Time]
the timezone observe DST from 3rd Saturday of October 23:59:59 to 3rd Saturday of February, 23:59:59.
Also, another non-official site seems to imply the same:
[http://www.icfsi2007.com/city_more.php will show
Manaus Time Zone is 1 hour less than Brasilia, Sao Paulo or Rio de Janeiro Time Zone (GMT - 03:00),
four hours behind of Greenwich Mean Time (GMT),
except during the period between late October and the end of February,
when daylight saving time is in force (GMT - 05:00 hours).
a) I do not interpret the timezone rules properly for America/Manaus, and there is a DST being observed there.
If so, please let me know how I should read the above rules/timezone information.
b) Microsoft timezone is incorrect
c) Olson data is incorrect
d) The Microsoft timezone [(GMT -4:00) Manaus - Central Brazilian Standard Time] does not
correspond to the Olson's America/Manaus timezone
Your opinion would be appreciated
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