Upcoming DST changes in Brazil–2011-2012

Article
10/11/2011

Disclaimer: The information in this document is written based on the decree # 6.558 published on September 8th of 2008 by the Brazilian Government.

The steps provided in this bulletin were created to mitigate the impacts that the daylight saving time may cause for customers in Brazil. These are the impacts primarily anticipated at the time this document was written, and the effects that customers may face are not restricted to them.

The suggested actions on this document might receive additional testing. This document contains information about how to modify the registry. Make sure that you back up the registry before you modify it. Make sure that you know how to restore the registry if a problem occurs.

The information described in this document may change without notice. In addition, customers should be aware that further guidance will be provided at any time by Microsoft.

1. Background – Brazil DST 2011/2012

Since 2009 Brazil follows a predetermined Daylight Time Saving schedule. Based on the government’s decree #6.558 published on September 8th of 2008 the DST period in Brazil has the following start and end dates:

· Daylight Saving Time starts at third Sunday of October at 12:00:00AM

· Daylight Saving Time ends at third Sunday of February at 12:00:00AM

The decree also establishes an exception for the DST end date when the 3rd Sunday of February coincides with the Sunday of Carnival. On the exceptions years the DST end date moves to the subsequent Sunday (forth Sunday of February).

The next exception will be for the DST period of 2011/2012. Due the fact the 3rd Sunday of February in 2012 is the Sunday of Carnival the end of the DST will be on 02/26/2012 instead of 02/19/2012.

For the year of 2011/2012, the Brazilian daylight saving time is defined as follows:

· Daylight Saving Time starts at third Sunday of October (10/16/2011) at 12:00:00AM

· Daylight Saving Time ends at fourth Sunday of February (02/26/2012) at 12:00:00AM

2. CHANGES FROM PREVIOUS YEARS

On October 3rd of 2011 the Bahia’s Governor announced that starting in 2011 the state will follow the DST period. The official announcement can be found on the following website:

https://www.comunicacao.ba.gov.br/noticias/2011/10/03/governador-jaques-wagner-anuncia-adesao-da-bahia-ao-horario-de-verao

For customers located on the state of Bahia the recommendation is to change the time zones of the machines from “(UTC-03:00) Cayenne, Fortaleza” to “(UTC-03:00) Brasilia”. Instructions how to use scripts to move the machines to a new time zone can be found in our Latam Team Blog.

3. Additional Information

Since 2008, Microsoft implemented a Daylight Saving Time rule for the Windows Operating Systems which contains the following settings for the Brazilian time zones - (UTC -3:00) Brasilia and (UTC -4:00) Cuiaba:

· Daylight Saving Time starts at third Saturday of October at 11:59:59.999 PM

· Daylight Saving Time ends at second Saturday of February at 11:59:59.999 PM

Windows operating systems may be impacted by the Brazilian Carnival and if the first day of the entry/exit month is a Sunday.

Microsoft is aware of the exceptions. Starting with Windows Vista, Microsoft introduced the concept of the Dynamic DST.

Dynamic DST provides support for time zones that can change from one year to the next. The rules for the DST are stored on the registry and can be accessed by applications as a source of information about past and future DST dates:

Windows XP and Windows 2003 operating systems do not utilize the Dynamic DST entry[1]. On December 13th of 2011 Microsoft will

publish a cumulative hotfix that will include the rules for the end of the DST period in 2012 as a part of the regular schedule.

Windows Vista and newer operating systems already have the all the known exceptions for the Brazilian DST up to 2040 stored on the Dynamic DST key.

4. Recommendations for Windows users – Beginning of the Brazilian DST

There are no special instructions to transition to the beginning of daylight saving time (October 16th, 2011) for the following scenarios:

· Machines that are updated with any of the following updates available on Windows Update:

o KB2570791 - August 2011 cumulative time zone update for Windows operating systems

o KB2443685 - December 2010 cumulative time zone update for Windows operating systems

o KB2158563 - September 2010 cumulative time zone update for Windows operating systems

o KB981793 - May 2010 cumulative time zone update for Windows operating systems

o KB979306 - February 2010 cumulative time zone update for Windows operating systems

o KB976908 - December 2009 cumulative time zone update for Microsoft Windows operating systems

· Machines that are updated any of the following updates not available on Windows Update:

o KB2443367 - Hotfix available for Windows daylight saving time support for Chile, Egypt, and Morocco

o KB2519231 - A hotfix is available to update the Daylight Saving Time for Chile for Windows Operating Systems

o KB 981128 - A hotfix is available to update the Daylight Saving Time for the "(UTC-04:00) Asuncion", “(UTC+12:00) Fiji” and “(UTC-04:00) Santiago” time zone for Windows Operating Systems

· Machines adjusted according to the guidelines published on the Latam Blog last year.

5. Recommendations for Windows users – END of the Brazilian DST

For Windows Vista, Windows 2008, Windows 7 and Windows 2008 R2 there are no special instructions to transition to the end of daylight saving time (February 26^th, 2011) for the following scenarios: