[tz] Changes in daylight saving rules in Brazil

Brian Inglis Brian.Inglis at SystematicSw.ab.ca
Wed Nov 6 03:42:20 UTC 2019

On 2019-11-04 10:20, Alexandre Henrique Soares Dias wrote:
> My name is Alexandre Dias and I'm a Data Scientist at a Brazilian Startup called
> Looqbox. As an R programmer and knowing that R uses the international standard
> IANA time zone rules. I would like to inform that the current Brazilian
> government changed daylight saving rules for "America/Sao_Paulo" timezone. This
> changes occurred this year and many devices are operating under the wrong hour
> of the day.
> Usually, at this time of the year we had to advance our clock by one hour going
> from -03 GMT to -02. However, as I said, this is no longer the rules and the
> clocks must remain -03 GMT. Following there is a print of this
> phenomenon showing that R is display and returning the wrong time for my timezone:
> image.png
>  <https://files.slack.com/files-pri/T0NA05E3Y-FQ4LFH6CV/image.png>
> The correct output should be "2019-11-04 13:25:27 -03". 
> Given the problems that may arise from this kind of behavior, I kindly ask you
> to apply the changes I informed above as soon as possible.

If time zone or DST changes have been announced publicly in advance and are
common knowledge in your region, someone will have reported it to the list, and
the data will have been updated.
Exceptions are when governments provide no advance public notice of changes
(Turkey!), only inform major tourist and/or airline organizations, or provide
vague or imprecise details in announcements, and are shocked when systems show
incorrect time for weeks afterwards, as IT support wait for official updates.

When these updates are picked up by your systems vendors and made available for
your systems, depends on their promptness in picking up and progressing the
updates through their processes, but mainly on how promptly your local IT
support apply those changes to your systems once available, and they should be
your first point of contact if there are time discrepancies on your systems.

If you are your own IT support, you are responsible for finding out how to apply
such changes to your systems, and how to find out when they are available.

Some system distributions may be poorly supported and you may have to prompt
them to be more timely in applying and propagating time zone and DST updates.
Some smartphone vendors and telcos are slower providing updates for older and/or
lower volume handsets and you should complain to your telco to be more timely
providing time zone and DST updates and/or announcing workarounds.

Take care. Thanks, Brian Inglis, Calgary, Alberta, Canada

This email may be disturbing to some readers as it contains
too much technical detail. Reader discretion is advised.

More information about the tz mailing list