Daylight Saving Time in Brazil

Avi Alkalay avi at
Thu Oct 13 00:24:07 UTC 2005

I'm waiting for this discussion to happen since I wrote that HOWTO.
Ironically, I found this thread in my GMail SPAM folder.

In my research for the HOWTO I couldn't find any standards for brazilian
timezone names. This fact didn't surprise me.... So I invented one.

The updated brazilian zic file is being maintained by me and contributors

Contributors keep sending me data for other LatAm countries, found there

I proposed this:

# BREST: East of Brasilia. Fernando de Noronha.
# BRST:  Brasilia, São Paulo, Rio, Northeast, South etc
# BRWST: West of Brasilia. Mato Grosso, Manaus
# BRAST: Acre.

# In daylight saving time, letter 'S' changes to 'D'.

I have a friend at and we discussed a litlle bit on how
to propose this as a standard for Brazil. In fact he is now the<>'s
general manager. We didn't go further with the discussion, and nothing
happened in the end, but we agreed that this is something to be defined
together with the Observatorio Nacional.

I'll be more than happy to help making this - or any other better convetion
- to become a standard.


On 10/11/05, Ronaldo Vasconcellos <ronaldo at> wrote:
> Hi Paul!
> I know Avi Alkalay, AFAIK he still works in IBM Brazil (I did). Let´s wait
> for his answer.
> I agree with you - the english term more similar to ours ("Horario de
> Verao") is Summer Time. But DST (Daylight Saving Time) seems to be the
> most popular around the globe.
> We learned that applications such as MySQL are affected by using
> non-GLIBC-compliant abbreviations. Are you aware of something like that?
> I hope we together solve this confusion. As I stated in my last message,
> there should be a FAQ entry. The only clear explanation is on
> "glibc-x.x.x/timezone/southamerica", too hidden :-)
> Regards,
> --
> Ronaldo C Vasconcellos
> Security Incidents Response Center
> Brazilian Research and Academic Network
> On Mon, 10 Oct 2005, Paul Eggert wrote:
> > Date: Mon, 10 Oct 2005 09:48:29 -0700
> > From: Paul Eggert <eggert at CS.UCLA.EDU>
> > To: Ronaldo Vasconcellos <ronaldo at>
> > Cc: The GNU C Library Steering Committee <glibc-sc at>,
> > Alexandre Oliva <aoliva at>, tz at, avi at
> > Subject: Re: Daylight Saving Time in Brazil
> >
> > As far as I can see, the abbreviations used in the above-referenced
> > table are merely examples and are not meant to be recommendations.
> > Abbreviations like "BRDT" would not correspond to common Brazilian
> > practice, which is to use the Portuguese equivalent of "summer time"
> > rather than "daylight time".
> >
> > As is stated in the tz tables' comments, in 1999 I invented the
> > abbreviations BRT/BRST, AMT/AMST, etc., that are used in the current tz
> > tables for Brazil. As far as I know nobody else has needed, or uses,
> > English-language acronyms for the Brazilian time zone. However, should
> > an alternate tradition arise in practice, of course we'd prefer to use
> > the English-language abbreviations that people are actually using, as
> > opposed to abbreviations that we have invented.
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